Scoping review of nurse triage in primary care

Abstract

Aim

Triage in the primary care setting is critical for ensuring timely access to and continuity of care for patients. This scoping review examines how nurse triage is implemented, including the types of nurses involved, settings, triage algorithms, classification systems, and outcomes.

Methods

A search of five electronic databases, including PubMed, CINAHL, EMBASE, Web of Science, and Cochrane Central, was conducted in July 2025.

Results

Thirty-seven studies were included, and a narrative synthesis was used for data analysis. Nurse triage in primary care involves registered nurses, advanced practice nurses, nurse practitioners, and nurse specialists, working alone or in teams with doctors, administrative staff, or other healthcare professionals. Three types of triage algorithms were identified. Triage classification systems typically consist of 3 to 5 levels, including urgent, routine, or self-care. Computerized triage tools have been introduced in some countries. Nurses tended to overrefer pregnant women and febrile children. Overall, patients were generally satisfied with nurse triage services. This scoping review identified four key themes in primary care triage: team triage, triage algorithms, patient safety, and quality assurance.

Conclusion

Nurse triage in primary care serves as a first and continuous point of contact for patients and ensures patient safety by providing quality care. To improve the quality of nurse triage in primary care, team-based triage and triage nurse education and training would be beneficial.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12912-025-03740-3.

Background

The prevalence of chronic diseases continues to rise worldwide. As a result, health care expenditures are increasing, adding to the socioeconomic burden [1]. This underscores the growing importance of primary care in the effective management of chronic diseases [2]. Primary care is defined as “the first entry into the healthcare system that focuses on people, not diseases over a long period of time, provides services for all diseases except very rare ones, and coordinates and integrates services provided elsewhere by other providers” [3]. It is a patient’s first point of contact with health system and includes general practice, community pharmacy, dentistry, and eyecare [4]. Countries with adequate primary care tend to have lower major mortality rates and medical expenditures, as well as higher subjective health status [5].

Triage is defined as “To perform a preliminary assessment in order to determine the nature and degree of urgency of treatment required” [6]. Classifying patients into emergency, urgent, nonurgent, and self-care categories is essential in all healthcare settings where limited allocation of healthcare resources must be managed [7]. Traditionally, triage has been conducted predominantly in emergency rooms, military contexts, and during natural disasters. Compared with emergency departments (EDs), triage in primary care is still in the process of being standardized [8].

Patients are classified according to their status and care needs, with those requiring nonurgent care being considered primary care. These patients may be asked to visit clinics, be referred to specialists, or be cared for by primary care nurses who provide health information and advice [9]. Virtual care in primary care has expanded since coronavirus disease 2019 (COVID-19), with triage increasingly utilizing telephone calls and videos [10].

In primary care, nurse triage facilitates interactions between patients and providers, increasing the likelihood that patients will receive timely care. This leads to improved patient outcomes, reduced unnecessary emergency department visits, and cost savings [9, 11]. Despite these benefits, research on how primary care nurses triage and collaborate with other professionals remains limited. This scoping review aims to address this research gap by identifying the key aspects of nurse triage in primary care and exploring its potential to enhance patient outcomes and healthcare delivery. To avoid ambiguity, EDs are not considered part of the primary care setting in this study.

Aims

This review aims to examine the characteristics and extent of nurse triage in primary care. Specifically, it explores the types of nurses involved, settings, triage algorithms, classification systems, and outcomes.

Methods

Study design

This scoping review was conducted via the Joanna Briggs Institute (JBI) methodology for scoping reviews [12], and the Preferred Reporting Items for Systematic reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) checklist was used to ensure proper reporting of each section in this report [13]. The protocol was registered with the Open Science Framework (osf.io/sn5vd).

Search strategy

In July 2025, a search was conducted using five electronic databases, including PubMed, CINAHL, EMBASE, Web of Science, and Cochrane Central. A trained librarian contributed to the development of search strategies. Appendix A provides the detailed search strategy.

Inclusion criteria and exclusion criteria

The inclusion criteria were as follows: (1) all types of study designs; (2) published between 2000 and 2025; (3) applied triage in a primary care setting (excluding EDs); (4) included nurse triage; and (5) were written in English. No geographic restrictions were applied. The exclusion criteria were as follows: (1) non-peer-reviewed articles; and (2) abstract-only or inaccessible full texts. COVID-19-related studies were excluded after full-text review, as they predominantly focused on triage for COVID-19 testing or screening under exceptional pandemic conditions, rather than on routine primary care services.

Data abstraction

Covidence software was used for this scoping review. Initially, literature was searched in five databases and imported into Covidence, which automatically removed duplicate documents during the import process.

PHN, SDS, and DD were involved in screening and selecting studies. A pilot test of the title and abstract screening was performed on the first 30 documents by two independent reviewers (PHN and SDS), who discussed and resolved disagreements to refine screening criteria. Subsequently, independent screening was conducted, with any conflicts resolved through discussion involving a third author (DD).

Key data from the studies were collected and organized in a Microsoft Excel spreadsheet via a template created by the research team. This template included important details such as author, year, country, study design, aim, setting, sample size, and key findings.

Data analysis and synthesis

A narrative synthesis facilitates the integration of diverse questions, research designs, and interventions [14]. Therefore, in this study, a narrative synthesis approach was employed, encompassing an initial synthesis and exploration of relationships within and across studies. This process followed the four-step framework proposed by Popay et al. (2006) [14]. In the theory development stage, the necessity and relevance of nurse triage in primary care settings were identified. During the preliminary synthesis, 37 studies were reviewed to extract and summarize key features, including the types of nurses involved, care settings, triage algorithms, classification systems, and outcomes. In the exploring relationships phase, the findings were compared across studies to identify patterns in how nurse triage was used and what results it produced. Lastly, in the assessing the robustness of the synthesis phase, the research team reviewed the final summary tables to check the strength and reliability of the synthesis.

Results

Study demographics and characteristics (Fig. 1; Table 1)

Fig. 1.

PRISMA flow chart for literature selection. From: Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ 2021;372:n71. 10.1136/bmj.n71

Table 1.

General characteristics of the studies included in the scoping review (n = 37)

Author (year)	Country	Study design	Aims	Setting			Sample size(n)	Key findings
				PC in clinic	PC in hospital	Call center
Barnett (2009)	Australia	Descriptive	To analyze service referral and utilization patterns and examine service delivery as part of a quality improvement			√	2,571-2,892 calls annually (50–60 calls per week)	Triage nurses reported concerns about professional isolation, lack of formal education, difficulties in making decisions based on limited data as well as poor understanding of the role by users (patients and referrers).
Cariello (2003)	USA	Descriptive	To investigate service quality and cost from the perspective of callers using Computerized Telephone Nurse Triage (CTNT) for pediatric clients			√	300 Pediatric patients’ parents from 32 states, between 5pm-9pm	The caller rated the overall level of service quality highly (6.42 out of 7). The computerized telephone nurse triage saved a total of $15,183.00, or $54.42 per call.
Cox (2000)	UK	Descriptive	To compare sore throat management quality between practice nurses and GPs in a routine triage system	√			435(total) Practice nurse = 188 (consulted 44% of the patients) GPs = 247 (consulted 56% of the patients)	Outcomes like sore throat resolution, re-consultation, antibiotic use, and dissatisfaction rates were the same. Nurses saw younger patients (mean age 22.5 vs. 28.3 years) and gave more advice on home remedies (76% vs. 54%). Patients seeing the nurse had better perceptions of returning to normal health (64% vs. 53%) and quicker recovery (4 vs. 5 days).
Cynthia (2001)	USA	Case study	To identify effects of computerized telephone triage program		√		58 patients evaluated by telephone triage nurse	67%(n = 39) sent to ER appropriately, inappropriate referrals (n = 19); Evaluated by pediatrician: appropriate 89%(n = 52), inappropriate 11% (n = 6: duration of illness = 4, nature of illness = 1, other = 1)
Elliott (2020)	UK	Intervention	To examine if nurse-led triage helps manage demand for GP appointments in primary care	√			•Standard nurse-led triage = 24,060calls (2-year pilot) •Total Nurse Triage = 5,298calls (6-months pilot) •Patient satisfaction: 46 patients (female 30, male16)	Standard nurse-led triage: 13,113 GP appointments were saved by providing advice, issuing prescriptions or sick notes, or scheduling nurse appointments. Total Nurse Triage: 2,270 GP appointments were saved through referrals to dental, physiotherapy, or pharmacy services. Patient satisfaction: 93% of patients (N = 43) rated their experience as ‘excellent.’
Evans (2001)	UK	Intervention	To describe the development of a local solution for out-of-hours dental care provision in the UK			√	•Survey: 160 (GDP, dental staff) •Focus group interview: 32 (30 GDPs, 2 GP)	82% dentists considered the new system better than the existing system; 12% considered there was no difference; 6% worse than the previous system.
George (2005)	Australia	Descriptive	To describe a Peter James Centre model of triage in an aged persons mental health service			√	2,918 triage calls	Improved accessibility (increased contacts) and responsiveness. Developed the triage team: two triage officers (a psychiatric nurse and a social worker), a part-time registrar in psychiatry and consultant psychiatrist
Gibbons (2010)	UK	Descriptive	To provide guidance, entitled the Traffic Light System, to help GP and practice nurses determine the urgency of a referral.	√			-	Red: Immediate Blue: within 24 h Yellow: within one week Green: Not emergency
Giesen (2007)	Netherlands	Descriptive	To investigate whether triage nurses use national guidelines and examine the relationship between their performance and education/training.		√		118 triage nurses from 4 cooperatives	Triage nurses correctly estimated the urgency of 69% of 352 contacts and underestimated 19%. Triage nurses trained in the use of national telephone guidelines had a lower rate of underestimation of urgency. Nurses’ educational background had no significant effect on underestimation rates.
Gormley (2003)	UK	Intervention	To determine if triage by GPs or rheumatology nurses improves the positive predictive value of referrals to early arthritis clinics	√			4GPs, 2RNs, 96 patients	51% (n = 49) has inflammatory arthritis and GPs or RNs referred properly, evaluated by experienced rheumatologists. Significant stiffness in the morning or after rest and objective joint swelling were the most important clinical features.
Harmsen (2005)	Netherlands	Descriptive	To determine the actions of triage nurses at GP co-operatives when a child is suspected of having a UTI or presents with a fever	√			145 triage nurses	For suspected UTI, all triage nurses requested a urine sample, but only 70% gave instructions on how to collect the urine. There is a potential for over-diagnosis of UTIs, as nurses often request GP visits for children with fever without a clear focus, even when UTI is not their primary suspicion.
Hathorn (2009)	UK	Descriptive	To establish the safety and effectiveness of nurse-led triage of otolaryngology out-patient referrals		√		2 consultants 2 specialist registrars 2 senior house officers 2 otolaryngology nurse (1 triage-grained) 100 referrals reviewed	Urgent 7%; soon 26%; routine 67% Showing good agreement with a senior ENT consultant on outpatient referrals. No cases were triaged inappropriately, and no urgent cases were missed.
Huibers (2012)	Netherland	Descriptive	To explore the impact of quality of consultation and estimated urgency on the appropriateness of decisions.	√			6,739 nurse telephone contacts of 623 triage nurses from 25 GPCs across the Netherlands	Significant correlation between quality of consultation and appropriateness of decision concerning urgency, follow-up advice and timing. An increase in urgency seemed to be related to a decrease of appropriate decisions for urgency estimations and an increase for follow-up advice and timing.
Kempe (2006)	USA	Descriptive	To assess compliance with nurse recommendations, death rates, and factors linked to under-referral in children triaged by a pediatric after-hours call center			√	32,968 calls from pediatric patients’ parents	21% received urgent (n = 7,039), 27% next-day (n = 8,862), 4% later visit (n = 1,360), and 48% home care recommendations (n = 15,707). The potential under-referral rate leading to hospitalization was 0.2% (1 per 599 triaged calls). Higher under-referral risk was linked to age (6 weeks or 12 years) and calls after 11 PM. Urgent and home care compliance rates were 74%, while next-day compliance was 44%. No deaths occurred within a week of after-hours calls.
Leydon (2013)	UK	Descriptive	To identify the process of delivering and seeking cancer related telephone help			√	52 (cancer patients, family, friends, and carers)	Four elements of the triaging process: Recognition, Self-identification, Formulation of the reason for calling, Request for further telling
Light (2005)	USA	Descriptive	To identify if parental advice from telephone triage nurses changed care location from the ED or doctor’s office to home			√	110 calls from pediatrics’ parents	Most parents in this study (n = 74) who called the Children’s Careline wanted their child seen either in the ED (n = 7) or in the physician’s office (n = 67). After triage, 21 parents sought formal care for their child. Thus, 53 parents performed home care for their febrile child as counseled by triage nurses. Most parents did follow home-care advice.
Magann (2022)	USA	Descriptive	To determine the agreement between advice given to obstetric patients by a call center and healthcare providers with varying experience			√	91 pregnant women	The call center nurses advised emergency care more frequently (51.7%) than the MFM (44%) and the APN (31.9%) but less frequently than the OB-GYN resident (57.1%). Advice given by nurses at an obstetric call center was highly consistent with the most skilled specialist (MFM) followed closely by OB-GYN resident or an APN.
Majeed (2023)	Qatar	Intervention	To improve categorization and identify training effectiveness.			√	470 medical records of patients from 26 health centers	After triage training, nurses improved their accuracy (63% →90%), correctly categorizing medical emergencies. Reducing over-triage 37% →10% The 5-minute physician response target in emergencies also improved from 48–55%.
Marklund (2007)	Sweden	Descriptive	To evaluate a telephone nurse triage model regarding referral appropriateness, patient compliance, and costs			√	362 Patients	Out of 362 patients, advice was adequate in 97.6% of cases. Compliance rates were 81.3% for self-care, 91.1% for primary health care, and 100% for A&E. Nurses improved care adequacy for 64.7% of self-care and 29.6% of A&E referrals. Cost savings per call were €70.3 for self-care, €24.3 for primary care, and €22.2 for A&E.
Marvicsin (2015)	USA	Descriptive	To identify the role and cost savings of an after-hour call system in averting ED visits			√	124 Health center callers	50% of the 124 calls averted an ED visit, saving an estimated $19,406. Another 43% of the calls were for non-urgent concerns and only 9(7%) calls resulted in an ED referral.
McGra (2000)	USA	Intervention	To identify if this process of triaging and self-care education was effective	√			35,231 patients	Central triage has demonstrated an annual cost avoidance exceeding 2,500,000$
McGrath (2008)	UK	Descriptive	To improve the quality and safety of telephone triage in after-hours services through a quality framework		√		-	The quality framework consists of three key components: training, protocols, and documentation. The service reduced the need for GP contact by over 50%, improved GP recruitment and retention, and was well-received by both GPs and consumers.
Moll van Charante (2006)	Netherlands	Descriptive	To explore determinants related to nurse telephone advice alone (NTAA)		√		GP 25, Nurse 8	Out of 1,421 calls, 1,030 (72.5%) were referred to a GP, while 391 (27.5%) received NTAA. The return consultation rate was 26.9% for GP referrals and 33.8% for NTAA. Nurses felt confident providing NTAA to younger patients with symptoms like earache, vomiting, or cough, but were more cautious with those showing multiple or serious symptoms, such as chest pain or abdominal pain. NTAA was more common at night than during the day or evening.
Navratil-Strawn (2014)	USA	Descriptive	To estimate the relationship between adherence to nurse recommendations and healthcare expenditures for callers to a Nurse HealthLine triage program			√	53,206 Nurse HealthLine triage calls	Total 53,206 calls, 29,438 adherent(55%), 23,768non-adherent(45%). Nurses were over three times more likely to recommend higher-level care, such as the emergency room, for those needing it. This guidance resulted in significant annual savings of $13.8 million, primarily benefiting Medicare, and yielded a positive return on investment of $1.59.
O’Cathain (2007)	Scotland	Descriptive	To assess nurse attitudes toward risk in telephone assessments using CDSS and their impact on decision-making			√	211 nurses	The response rate was 57% (265/464). Analysis of 231,112 calls matched to 211 nurses revealed that 16% (36,342 calls) were directed to self-care. Nurses in the top 10% recommended self-care three times more often than those in the bottom 10%. Community nurses were less likely to suggest self-care than those from acute settings. Much of the decision-making variation remained unexplained, and nurses’ risk attitudes did not significantly influence their choices, likely due to measurement limitations.
Richards (2000)	UK	Descriptive	To describe the changes required to introduce a nurse telephone triage system into a large primary care practice	√			-	Addressing workload and access issues in primary care requires a whole-systems approach. Key to success was empowering the nursing team through leadership, skills mix review, innovative resource use, team building, and collaboration among nurses, doctors, and reception staff. Time has been crucial in implementing these changes, and policymakers should recognize this in the evolving primary care landscape.
Richards (2002)	UK	Intervention	To compare GP and nurse workloads and costs of patient care for nurse telephone triage vs. standard same-day appointment	√			4,685 patient total (1,233 standard management & 3,452 the triage system)	Triage reduced the number of same day appointments with GPs but resulted in busier routine surgeries, increased nursing time, but significant increase in out of hours and accident and emergency attendance. Consequently, triage does not reduce overall costs per patient for managing same day appointments.
Richards (2004a)	UK	Randomized Controlled Trial	To determine if off-site triage by a nurse is a feasible option for primary care (workload and cost)	√			4,703 patients total (2,452 practice based triage & 2,251 NHS direct triage)	Patients in the NHS Direct group were less likely to have their call resolved by a nurse and more likely to see a GP. Their mean total time per patient was 7.62 min longer than the practice-based group. Costs were higher in the NHS Direct group by £2.88 per patient due to differences in patient contact points after triage.
Richards (2004b)	UK	Descriptive	To assess the impact of nurse telephone triage in primary care on the consulting behaviors of GPs		√		2,182 consultations (IG 1,102 & CG 1,080)	Patients in the triage system presented more health issues and received more consultations, prescriptions, and investigations, while referral rates to secondary care remained unchanged.
Scalvini (2005)	Italy	Intervention	To analyze a home-based telecardiology intervention in congestive heart failure patients, focusing on the role of nurse triage and one-lead ECG monitoring	√			3,767 calls from 230 patients with chronic health failure	In 2,417 of 3,767 calls, nurses took no action. In 418 calls, they recommended therapy changes, admitted 62 patients, arranged investigations for 243, and consulted GPs for 41. Nurses conducted 2,303 one-lead ECGs, identifying issues in 6% of cases, leading to beta-blocker adjustments for 79 patients.
Trip (2021)	Scotland	Descriptive	To describe the use and impact of the national cancer helpline			√	8,385 calls from 6,562 patients	Helpline use rose by 83.6% from 2016 to 2020, mainly due to increased in-hours calls. Of the calls, 41% needed professional review only, 24% required review and admission, and 35% received telephone advice only.
Eldh (2020)	Sweden	Qualitative	To describe healthcare staff’s experience with a digital communication system for patient encounters in primary care	√			21 health care staff at 5 primary care center	Patient-uploaded photos on the digital system provided supplementary data, enabling safer assessments and better agreement among the healthcare team during triage.
Goransson (2020)	Sweden	Qualitative	To describe nurses’ experiences of triaging patients at walk-in clinics at primary healthcare centers	√			12 RN from five different health centers	In-person interactions enabled nurses to use eye contact and physical exams for better assessments. Their expertise increased confidence, while collaboration with colleagues provided support when needed.
Holmström (2007)	Sweden	Qualitative	To explore user perspectives on decision aid software for telenursing			√	12 nurses	The decision aid software assists with assessment but lacks support for decision-making. Users noted inconsistencies between the software and actual practice, limited learning resources, and communication challenges with the software.
Rosen (2000)	UK	Qualitative	To examine the role of inter-professional collaboration in the development of NHS Direct, the new national telephone triage service			√	29 (Representatives of NHS Direct, local GPs, accident and emergency consultants, representatives of relevant health authorities, community trusts, community health councils)	The role of triage nurses in NHS Direct involved working independently of doctors, guided by computerized triage systems to assess patients, while doctors provided support for more complex cases.
Reblora (2021)	Singapore	Mixed method (observation + in-depth interview)	To explore the experiences of nurses working in triage stations of primary health care centers	√			22 RN	The 19 participants valued their nursing experience, which helped them recognize common diseases and make initial assessments. Patient frustration due to long waiting times, particularly among younger patients who had high expectations influenced by instant access to information via mobile devices. Teamwork with physicians was essential, but some nurses felt that electronic communication was inadequate for triage, expressing a preference for face-to-face discussions to convey their assessments more effectively.

Note. A&E = Accident & Emergency; APN = Advanced Practice Nurse; CDSS = Clinical Decision Support System; ED = Emergency Department; ENT = Ear, Nose, and Throat; ER = Emergency Room; GDP = General Dental Practitioner; GPs = General Practitioners; MFM = Maternal-Fetal Medicine; OB-GYN = Obstetrics and Gynecology; RN = Registered Nurse; UTI = Urinary Tract Infection

Figure 1 shows a PRISMA flow diagram of this study. Initially, 1,978 articles were identified. After removing the duplicates, 1,136 studies remained. Following title and abstract screening, 1,030 articles were excluded for failing to meet the inclusion criteria. The full texts of 89 articles were subsequently screened. Seventeen articles were excluded because their full texts were unavailable despite efforts to obtain them from the university library. Ultimately, 52 articles were excluded based on eligibility criteria, including 14 not involving triage, 11 not involving nurses, 9 related to COVID-19, 6 unpublished studies, 5 with unsuitable study designs, and 7 not conducted in primary care settings. No additional articles were included through manual searching. In total, 37 studies were included in this study.

Table 1 summarizes the general characteristics of the 37 studies included in this scoping review. The study designs were diverse, including 22 descriptive studies (59.5%), 6 intervention studies (16.2%), 6 qualitative studies (16.2%), 1 randomized controlled trial (RCT, 2.7%), 1 case study (2.7%), and 1 mixed-method study (2.7%). All the articles were published between 2000 and 2025. The most frequently published years were 2000–2009 (n = 23, 62.2%), followed by 2020–2025 (n = 9, 24.3%) and 2010–2019 (n = 5, 13.5%).

Studies were conducted in the UK (n = 12, 32.4%), the USA (n = 7, 18.9%), Sweden (n = 6, 16.2%), the Netherlands (n = 5, 13.5%), Scotland (n = 2, 5.4%), Australia (n = 2, 5.4%), York, England (n = 1, 2.7%), Singapore (n = 1, 2.7%), and Qatar (n = 1, 2.7%). The most studied setting was the call center (n = 17, 45.9%), followed by primary care in clinics (n = 14, 37.8%) and primary care in a hospital (n = 6, 16.2%).

The reported sample sizes across the included studies ranged widely, from 6 to 53,206, representing various units such as triage calls, patients, healthcare professionals, and medical records. Due to this heterogeneity, calculating a single mean or median sample size was not reported.

Triagers (Table 2)

Table 2.

Characteristics of nurse triage in primary care (N = 37)

Author (year)	Triager	Team or alone	Triage algorithm	Triage Classification	Tool
Barnett (2009)	RN	Team (specialist medical, nursing, and allied health personnel)	Enrolled and un-enrolled patient can call →nurse answers (using triage response scale)	1) emergency services respond within 10 min (ambulance, police, fire brigade) 2) face-to-face assessment is required within 1 h 3) face-to-face assessment is required within the next business day 4) referrals that are not appropriate for face-to-face assessment by a public mental health service clinician
Cariello (2003)	RN	Alone	Patient self-report symptom via phone →RN assesses and triage patients using computer-accessed clinical algorithms →patient received feedback via phone	1) emergency care: 911 or Emergency room 2) urgent care: Call PCP/MD 3) routine care: PCP/MD office visit 4) home care/ complementary medicine/do nothing	Computerized telephone nurse triage: 24 h a day, 7 days a week. no charge for cost
Cox (2000)	Practice nurse	Alone	Patient with sore throats visit clinic →RN assesses and triage patients using sore throat protocol. Triage time limited 5 min. →patient received feedback	1) refer to doctor for assessment 2) penicillin erythromycin 3) aspirin gargles, rest, fluids. Review 1 week if no improvement sooner if deteriorate.
Cynthia (2001)	RN with a week training	Alone	Patient check computerized assessment form →Centramax software produce protocol (‘yes’ or ‘no’) →RN assesses and triage patients using produced protocol → patient received feedback	1) life threatening 2) emergent 3) urgent 4) non-urgent 5) advice	Centramax software
Eldh (2020)	District nurse(nurse specialist)	Alone			Digital communication system
Elliott (2020)	RN	Team (nurse, GP, receptionist)	Standard nurse-led triage service Patient visit or call to request same-day appointments →RN assess and triage patients →patient received feedback Total nurse triage service Patient call to request same-day or routine appointments →RN assess and triage patients →patient received feedback	1) advice only 2) appointment with nurse 3) routine GP appointment 4) same-day appointment with GP 5) prescription or ‘sick note’ 6) referral for further care 7) GP home visit 8) emergency 999 call
Evans (2001)	Nurse got training session	Team (GP or GDP, nurse)	Patient call →RN records the patient’s demographic information, history, chief complaint using computerized assessment form →Centramax software produce protocol (‘yes’ or ‘no’) →RN triage patients using produced protocol → patient received feedback	1) self-care at home 2) transfer to the on call dentist 3) visit an accident & emergency department	Developed computer driven decision support software, examined by 16 dentist
George (2005)	psychiatric nurse, RN	Team(psychiatric nurse, social worker, psychiatrist)	Patient call community team →administrative assistant screen and refer to the triage officer if need →nurse triage patient → patient received feedback - triage hour: 8:30 to 17:00 Monday to Friday. - weekends: senior nurse on the acute inpatient unit	1) advice 2) referral	Peter James Centre model of triage Form a triage team, meet every morning & review; monitoring waiting list; liaising with ER; being involved with the GP Shared Care Committee; attend the monthly Community Team Leaders meeting
Gibbons (2010)	RN	Alone	Patient visit clinic →RN assess and examine patient using traffic light system →patient received feedback	1) immediate contact on call ophthalmologist at local hospital 2) within 24 h make appointment via local eye clinic 3) within one-week fax referral letter to eye clinic 4) not emergencies, routine referral if unable to manage in practice	Traffic light system
Giesen (2007)	RN	Team (nurse, GPs)		1) life threatening: Triage nurse informs GP at once. GP interrupts work and immediately goes to patient. 2) acute: GP goes to patient as soon as possible—within 1 h at most. 3) urgent: Complaint(s) should be evaluated within 2 h for medical or emotional reasons. 4) routine: Triage nurse arranges an appointment with the GP or gives advise him/herself.
Goransson (2020)	RN	Alone
Gormley (2003)	RN	Alone	Patient visit hospital →RN assess and judge if the patient has inflammatory arthritis or not→ patient received feedback
Harmsen (2005)	RN(mainly GP nurse)	Team (RN, GP)	RN assesse survey vignettes → patient received feedback	GP co-operative or urine sample or instructions about collecting urine or advice given	Telephone triage guide (not mandatory)
Hathorn (2009)	Triage-trained nurse	Alone		1) urgent: less than 2 weeks 2) soon: less than 6 weeks 3) routine: less than 18 weeks
Holmström (2007)	RN	Team (RN, GP)			Decision aid software programs for telenursing
Huibers (2012)	RN	Alone	Patient call →RN assess and triage patients using HAAKplus instrument →patient received feedback	1) life-threatening 2) acute 3) urgent 4) non-urgent	Quality of consultation: HAAKplus instrument Appropriateness of triage: 3 items of HAAKplus: urgency estimation, follow-up advice and timing
Kempe (2006)	RN with over 4 years of pediatric clinical experience and with specialized training in telephone triage	Team (RN, pediatrician)	Patient call →RN assess and triage patients using computerized protocols that guide them through a sequence of questions, the answers to which dictate a recommended triage disposition. →RN can adjust disposition decision only with the agreement of a second triage nurse.	1) urgent(visit within 4 h) 2) next day (visit in 4 h but within 24 h) 3) later visit (visit in 24 h) 4) home care (care at home without a visit)	Computerized protocols
Leydon (2013)	specialist nurse	Team (frontline call-taker, specialist nurse, welfare rights team)	Patient call →frontline call-taker answers the call and collects routine data →frontline call-taker may determine that a caller needs to be triaged to a specialist nurse if they are calling with a medical query (question about symptoms, treatment, or prognosis). →specialist nurse triage patients →patient received feedback
Light (2005)	12 pediatric nurses trained in the use of standardized triage protocols	Alone	Patient call →RN assess and triage patients using computerized charts →patient received feedback	1) go to ED 2) be Seen Immediately 3) be Seen in 24 h 4) home care
Magann (2022)	Call center nurse	Team (call center: 22 full-time nurses, 5 patient service coordinators, 8 appointment center personal)	[call center process] Patient call call-center →patient self-report their symptom using computer software menus designed to provide questions based on initial complaint and responses. →RN review the records and triage patients →patient received feedback	1) self-care: advice given only, no prescriptions were called in for the patient 2) self-care with prescriptions 3) appointment: needs to be seen sooner in the clinic that her regularly scheduled appointment 4) emergency: come to the emergency room or to labor and delivery depending on her gestational age.	Computer software menus with the obstetric triage protocols (labor and delivery experience, trained computer software), Women’s health APN, a fourth year OB-GYN resident, MFM
Majeed (2023)	RN	Team (greeter nurse →triage nurse →triage physician)	Patient arrives at the triage clinic →initial encounter with greeter nurse →if patient are not critically ill, appropriately managed in health care center or refer to secondary/tertiary care. →If patient critically ill, encounter with triage nurse →triage nurse assess and triage patients →patient received feedback	[greeter nurse] 1) care our health care center 2) refer triage nurse 3) refer secondary/tertiary care [triage nurse] 1) emergency: triage physician after 5 min waiting time 2) priority: triage physician after 30–90 min waiting time 3) routine: within shift
Marklund (2007)	RN	Team (nurse, pharmacists, dentist, GPs, hospital doctors all over the country)	Patient call →RN assess and triage patients based on the guidelines set out in the decision support and experience → patient received feedback	1) self-care advice 2) refer to primary health care center 3) refer to accident and ED	Digital decision support model
Marvicsin (2015)	NP, nurse midwives	Alone (NP or midwives)	Patient call →NP or midwives triage caller →patient received feedback	1) ER/urgent care 2) ER or urgent care visit was averted 3) information or advice only
McGra (2000)	RN	Team (RN, physician, nurse practitioner, physician assistant)	Patient call →RN triage patients →patient received feedback	1) emergency center 2) same-day appointment at a primary care clinic or the urgent care clinic 3) self-care education
McGrath (2008)	RN	Team (RN, GP)	Patient call →RN triage patients using paper protocols. But telephone triage nurse is not permitted to make a diagnosis over the phone → patient received feedback	1) ambulance 2) nursing advice and reassurance 3) local medical appointment the next day 4) advice or treatment from their local doctor on call 5) refer to the local ED(patient requiring assessment)
Moll van Charante (2006)	RN	Team (GP & nurse)	Patient call →RN assess and triage patients →patient received feedback	1) nurse telephone advice alone 2) refer to GP on duty 3) referral to A & E
Navratil-Strawn (2014)	RN with AARP certification and Medicare immersion training	Team (triage nurse, Nurse HealthLine staff for non-triage calls)	Patient call →RN assess and triage patients →patient received feedback	1) ER to a lower level of care: the caller’s pre-call intent was to seek care in an emergency room but the nurse recommended a lower level of care, such as an urgent care visit or a visit to a doctor’s office or self-treatment at home 2) non-ER/office visit to a lower level of care 3) same level of care: the nurse agreed with the caller’s pre-call intent and then provided information to prepare the member for that level of care 4) non-ER level of care to ER 5) non-ER visit to higher, on-ER level of care
O’Cathain (2007)	Telephone assessment nurses: mean age 42, length of nursing experience = 20yr	Alone	Patient call →RN assess and triage patients →patient received feedback	1) self-care 2) service at a later date 3) immediate contact with a service	Computerized decision support software
Reblora (2021)	RN	Team (doctor, nurse)
Richards (2000)	RN	Team (1 triage nurse, 1 triage doctor)	Patient call →receptionist initially triage patients →RN assess and triage patients using computer-based protocol →patient received feedback	1) telephone advice 2) nurse appointment(same day or routine) 3) doctor appointment(same day or routine) 4) doctor home visit	Computer-based protocol
Richards (2002)	Practice nurse	Team (practice nurse, receptionist)	Patient call →RN assess and triage patients using computerized management protocols →patient received feedback	1) telephone advice only 2) same day nurse appointment 3) same day GP appointment 4) home visit 5) routine nurse or GP appointment.	Computerized management protocols
Richards (2004a)	RN	Nursing team (one full-time nurse, 9 practice nurses)	[Practice based triage] Patient call to requests same day appointment →RN assess and triage patient using several clinical protocols on the patient record system, not computerized algorithms →patient received feedback [NHS Direct triage] Patient call to requests same day appointment →RN assess and triage patient using NHS Direct computerized decision making algorithms →patient received feedback	Telephone support alone, refer to GP, same day appointment with a nurse or GP, home visit, routine appointment with a nurse or GP	NHS Direct computerized decision making algorithms in NHS Direct triage team
Richards (2004b)	6 practice nurses, who had received 30 h of minor illness management training	Team (GP, practice nurse)	Patient call to requests same day appointment →RN assess and triage patient using computerized management protocols →patient received feedback	1) telephone advice only from the nurse or GP 2) same day nurse appointment 3) same day GP appointment 4) home visit 5) routine nurse or GP appointment	Computerized management protocols
Rosen (2000)	RN	Team (nurse, GPs)
Scalvini (2005)	RN	Alone	Patient transmit one-lead ECG recording by a mobile or fixed telephone →nurse reporting and interactive teleconsultation(providing information on health status, symptoms, weight, diuresis, drug adjustment, optimization), tele-assistance, monitoring →patient received feedback	1) telephone consultation 2) refer further investigations and consultation with GP 3) refer hospital
Trip (2021)	Oncology nurse or trained non-clinical handler	Team (oncology nurse, non-clinical handler)	1) Patient call in hour(weekdays 8:00 to 17:00) →oncology nurse assess and triage patient →patient received feedback 2) Patient call in out of hours →trained non-clinical handler initially triage patient using the United Kingdom Oncology Nursing Society toolkit →patient received feedback	1) advice 2) oncology department review 3) GP review 4) referred to their local accident and ED

Note. A&E = Accident & Emergency; APN = Advanced Practice Nurse; ED = Emergency Department; ER = Emergency Room; GPs = General Practitioners; hr = hour; MD = Medicinae Doctor; MFM = Maternal-Fetal Medicine; min = minutes; NP = Nurse Practitioner; OB-GYN = Obstetrics and Gynecology; PCP = Primary Care Practitioner; RN = Registered Nurse

Table 2 presents an overview of nurse triage characteristics across the 37 included studies, including the type of triager, whether triage was performed by nurses alone or as part of a team, the use of triage algorithms, and the classification systems employed.

In all 37 studies included in this scoping review, nurses were involved in the triage process. The majority of studies (n = 30) involved registered nurses (RNs), while other types of nurses—such as specialist nurses (n = 3) [15–17], nurse practitioners (NPs) (n = 1) [18], advanced nurse practitioners (ANPs) (n = 1) [19], psychiatric nurses (n = 1) [20], and oncology nurses (n = 1) [21]—were also represented.

Among the nurses working as triage nurses, only 24.3% of studies (9 out of 37) reported that nurses had received education or training related to triage. The training encompassed telephone triage [22], triage computer software programs [19, 23], and triage training [24]. Navratil-Strawn et al. included RNs with American Association of Retired Persons (AARP) certification and Medicare immersion training [25], whereas Richards et al. involved six practice nurses who had received 30 h of minor illness management training [26]. Evans et al. (2001) conducted training sessions [27], Light et al. had 12 pediatric nurses specially trained in the use of standardized triage protocols [28], and Cynthia et al. included RNs who underwent a week of training [29]. Barnett’s concerns focused on the dearth of formal education among triage nurses, which is a crucial impediment to effective decision-making [30]. Halmambetova et al. developed educational materials for digital chat-based self-education; however, the training primarily focused on the technical use of the system [23].

Triage performed by nurses alone and in team settings (Table 2)

Among the 37 studies reviewed, nurses performed triage alone in 13 studies (35.1%) [15, 17–18, 24, 28–29, 31–37], whereas 24 studies (64.9%) were led by teams that included nurses. First, nurses were tasked with triaging patients alone in the following areas: ENT [24, 32], pediatrics [28–29, 31], ophthalmology [33], rheumatology [35], and general practices [15, 18, 34, 36–37]. In two studies, triage was carried out during after-hour calls [18, 31].

Second, team triages have been divided into three categories: teams with nurses and doctors (n = 14, 58.3%), teams with nurses and administrative staff (n = 6, 25.0%), and teams with nurses and other healthcare professionals (n = 4, 16.7%). Teams consisting of nurses and doctors (n = 14, 58.3%), including general practitioners (GPs), general dental practitioners (GDPs), and pediatricians, are described in the following studies [22, 26–27, 38–48]. Teams composed of nurses and administrative staff (n = 6, 25.0%) were detailed in the following studies: Elliott et al., which included a nurse, GP, and receptionist [49]; Magann et al., which included nurse patient service coordinators and appointment center personnel [19]; Navratil-Strawn et al., which featured a triage nurse and Nurse HealthLine staff for nontriage calls [25]; Richards et al., which consisted of a nurse and receptionist [50]; Halmambetova et al., which consisted of a nurse and administrator [17]; and Trip et al., which included an oncology nurse and a nonclinical handler [21].

Teams composed of nurses and other healthcare professionals were described in 4 studies (16.7%): Barnett et al. featured specialist medical, nursing, and allied health personnel [30]. George et al. included a psychiatric nurse, social worker, and psychiatrist [20]. Leydon et al. included a frontline call taker, a specialist nurse, and a welfare rights team [16]. Marklund et al. (2007) involved nurses, GPs, hospital doctors, pharmacists, and dentists [51].

Triage algorithms and tools (Table 2)

30 out of 37 studies (81.1%) presented a triage algorithm. These were categorized into three types based on who initiates the assessment and how the information is processed. While the initial procedures differed, in all cases, patients initially contacted services either by telephone or in person, and triage nurses ultimately provided clinical recommendations, including self-care advice, booking clinic appointments, referring to appropriate services, or advising an ER visit.

In the first type (n = 22, 73.3%), (1) a triage nurse conducts a symptom assessment and (2) provides recommendations [18–19, 22–23, 25–28, 30–33, 35–38, 40, 44, 47, 49–51].

The second type (n = 3, 10.0%) starts with (1) the patient answering protocol-based questions. (2) A triage nurse then performs a symptom assessment based on the protocol answers and (3) provides recommendations [17, 19, 29].

The third type (n = 5, 16.7%) involves (1) an initial symptom assessment by a receptionist, a trained handler (nonmedical staff), an administrative assistant, or a greeter nurse. (2) After this preliminary step, a triage nurse conducts a comprehensive symptom assessment and (3) provides recommendations [16, 20–21, 42, 46].

Additionally, 11 out of 37 studies (29.7%) adopted computerized protocols or decision support systems [16, 19, 21–23, 27, 29, 31, 33, 47, 50]. RNs utilize computerized protocols or decision support systems to assess and triage patients. Triage tools commonly used in emergency settings, such as the Emergency Severity Index (ESI) or the Manchester Triage Scale (MTS), were not employed in any of the included studies. Instead, the studies used computerized decision support tools specifically developed or adapted for the primary care context (e.g., Centramax software, NHS Direct algorithms).

Triage classification

29 out of 37 studies (78.4%) incorporated triage classification, and we identified two predominant types of triage classification systems: Thirteen of the included studies employed a three-class triage system, whereas fourteen employed a four-class or higher triage system (Table 2).

The 3-class triage systems are as follows (n = 13, 35.1%) [19–20, 23–24, 27, 32, 37, 38, 40, 42–43, 46, 51]:

1. Self-care at home: information or advice given only

2. Urgent/routine care: an on-call visit, same-day appointment, or self-care with prescriptions or examination

3. Emergency care: A visit to the emergency department or a home visit

The four-class triage systems include (n = 13, 35.1%) [18, 21–22, 25–26, 28, 30–31, 33, 44, 47, 49–50]:

1. Self-care at home: information or advice given only

2. Routine care: regular or routine hour appointment or consultation by a Doctor via phone

3. Urgent care: an on-call visit or same-day appointment

4. Emergency care: A visit to the emergency department or a home visit

Among the sites that implemented the four-level triage system, three included a life-threatening level and were categorized as follows (n = 3, 8.1%) [29, 36, 39]:

1. Nonurgent: advice only

2. Urgent

3. Emergent or acute

4. Life-threatening

Key findings of the articles reviewed

The categorization of settings varies, making direct comparisons difficult; however, nurse triage decisions generally show good agreement with those of doctors [24, 35]. In Hathorn et al. (2009), an ear, nose, and throat (ENT) nurse’s triage decisions agreed with those of a senior consultant in 80% of cases (κ = 0.62) [24]. Similarly, Austin et al. (2003) found that trained rheumatology nurses showed substantial agreement with rheumatologists (κ = 0.79), accurately identifying 88% of appropriate and 91.5% of inappropriate referrals [35].

Nurse triage also influenced healthcare utilization. In primary care, the proportion of patients receiving home care because of RN triage ranged from 16 to 53% [28]. Those who would previously have visited the clinic were now managing their condition at home. However, several studies reported instances of over- or under-triage by nurses. Nurses tended to overrefer patients with obstetric problems and children with fever [19, 25]. Underestimation of urgency occurred in 0.2–19% of cases [22, 39], and the rate of inappropriate referrals was 11% [29].

Despite these concerns, patient satisfaction with nurse triage was high. Patients, including parents of pediatric patients, rated their triage experience as “excellent” [49] or “high” [31]. Triage training was shown to improve accuracy; for instance, Majeed et al. (2023) reported a measurable improvement in nurse triage performance following training.

Discussion

We reviewed 37 research articles involving nurse triage in primary care. The years 2000–2009 was the most often published years. This trend may reflect the growing demand for telephone triage services around the world during this period. NHS Direct, which serves England and Wales, was founded earlier in 1998 [52], whereas Scotland’s NHS 24, a national health center offering telephone medical consultation, was launched in 2001 [53]. In Sweden, a patient sorting system incorporating triage and a nurse-on-call service within primary healthcare centers was implemented more recently in 2015 [54]. The surge in publications from 2000 to 2009 may indicate a growing focus on evaluating the effectiveness of these services, as they were adopted at the national level. Nurse triage is performed in various primary care settings, including call centers, clinics, and primary care in the hospital, and is performed by nurses alone or in teams. Primary care represents the initial point of contact for patients seeking health care, and the accuracy of primary care triage is paramount in ensuring the timely delivery of care. In this review, we explored four strategies for the implementation and expansion of primary care triage.

Nurse triage systems in primary care vary across countries due to differences in healthcare infrastructure, policies, and the scope of nursing roles. For example, the United Kingdom has a dual approach: (1) a national call center (NHS 111 in England and Wales, NHS 24 in Scotland) [16, 21, 27, 37, 48], and (2) triage services in GP clinics [32–33, 46–47, 49–50]. In call centers, non-clinical call handlers receive the initial patient contact using structured protocols. Nurses then review the information and call patients back for clinical assessment [53]. In GP clinics, nurses often serve as the first point of contact [32–33, 47, 50]. Similarly, Sweden operates a centralized national call center, where nurses directly respond to patient calls [41]. In the United States, nurse triage is also typically delivered through call centers. However, unlike in the UK or Sweden, these services are not nationally coordinated. Instead, they are run by individual health systems, insurance companies, or providers [18, 22, 28, 31]. Overall, nurse triage is mostly done by telephone. These differences make direct comparisons difficult, but they offer valuable insights for future development of nurse triage systems in primary care.

Triage teams

Primary care triage is often team-based. Since the beginning of the COVID-19 pandemic, virtual care has increased, facilitating interprofessional team care. Responding as a triage team can provide patients with more accurate triage based on comprehensive patient information from multiple disciplines. When nurses conducted triage alone, they were assisted by a computerized triage system or structured guidelines to ensure consistent care.

Timely access to patients’ information was also crucial for triage nurses. Since telephone triage requires decisions to be made without visual confirmation of the patient’s needs, having comprehensive information about the patient’s health needs helps ensure accurate decision-making. In a recent study [15], patients uploaded a photo of the affected area to a digital system, which helped the triage team make better decisions. Virtual care using Zoom has also been on the rise since COVID-19. Taken together, primary care triage is team-based, and the use of virtual contacts can improve the quality of triage.

Triage algorithm

Primary care triage algorithms help nurses perform appropriate and accurate triage. Nurses or nurse practitioners conducted the initial assessments for patients in most studies. Only four studies, the assessments were performed not by nurses, but by two computerized systems, one receptionist, and one frontline call taker. Owing to the diversity of primary care services, it is difficult to establish a uniform triage system. In the UK, the Enabling Quality Improvement In Practice (EQUIP) triage guidelines, which are a national initiative, are continuously released. The purpose of the EQUIP guidelines is to identify patients and their primary care needs, collect patient information, and provide feedback. These types of guidelines can serve as important references for algorithm development in various primary care settings. The developed algorithms should be evaluated periodically to improve their usability [55].

Patient safety

In this review, nurse triage—when evaluated in terms of clinical judgment compared to general practitioners—was found to be acceptable, with kappa scores ranging from 0.66 to 0.78 [24, 35]. However, nurses tended to overestimate emergency referrals compared with their doctor counterparts. This phenomenon could be interpreted as a strategy of deferring decisions regarding patients with suspected emergencies or those at the borderline between emergency and routine care to their doctors, with the aim of ensuring patient safety [25, 40]. In contrast, nonemergency roles, such as the provision of self-care education and health information, were more active than other roles. This has a positive effect on patients’ ability to self-care, which results in a reduction in clinic visits.

Quality assurance of nurse triage

To improve the quality of triage, training based on updated guidelines is critical. First, triage training should include triage nurses as well as triage trainers. The apprenticeship method is frequently employed to train triage nurses. When trainers were trained on how to train new triage nurses, both mentors and mentees reported higher levels of satisfaction, and their triad congruence increased [39]. As nurses’ roles in primary care expand, triage algorithms and tools continually evolve. Therefore, triage training should include the latest algorithms and tools, along with guidance on applying them in primary care settings. Machine learning techniques will help in improving updated clinical prioritization to deliver better triage [46]. Consistency between triage nurses and general practitioners also needs to be regularly audited. In addition, patients’ experiences and triage nurses’ job satisfaction need to be evaluated to ensure quality assurance.

Lastly, nurse triage is necessary for the effective management of chronic diseases such as hypertension and diabetes in primary care. Longitudinal studies are essential to evaluate the level of chronic disease management. As artificial intelligence develops and expands into the medical field, it is urgent to provide education for nurses.

Limitations

Despite a thorough literature search, selection bias may still exist because we restricted the language to English and excluded grey literature. Since nurse triage in primary care is a relatively new concept, relevant information might be found in reports or news articles. Future research should consider including these types of sources as well. Nevertheless, this study is valuable because it provides an overview of nurse triage in primary care, offering insights into clinical practice, research, and policy-making.

Conclusions

This review examined the status of nurse triage applications and their quality in primary care, identifying four key themes for primary care triage: team triage, the triage algorithm, patient safety, and the quality assurance of nurse triage. The quality of nurse triage was found to be acceptable, and the review concluded that having a validated triage algorithm is essential for ensuring the quality of triage. Given the heterogeneity of primary care settings, it is recommended that each site adopt a triage process guided by national triage guidance. As virtual healthcare has been implemented and its application expanded, support from digital health care information would be beneficial for appropriate and correct triage in primary care.

Supplementary Information

Below is the link to the electronic supplementary material.

Abbreviations

ANPs

Advanced Nurse Practitioners

COVID-19

Coronavirus Disease 2019

ENT

Ear, nose, and throat

EQUIP

Enabling Quality Improvement In Practice

ESI

Emergency Severity Index

GDPs

General Dental Practitioners

GPs

General Practitioners

JBI

Joanna Briggs Institute

MTS

Manchester Triage Scale

NPs

Nurse Practitioners

PRISMA-ScR

Systematic reviews and Meta-Analyses Extension for Scoping Reviews

RNs

Registered Nurses

Author contributions

All authors have checked and given final approval of the version to be published. We agree to be accountable for all aspects of the work, ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.Conceptualization and/or Methodology: Park HN, Shin DS, Duong David; Search strategy and Methodology: Carrie; Data curation and/or Analysis: Park HN, Shin DS, Duong David; Project administration and/or Supervision: Shin DS, Duong David; Resources and/or Software: Park HN, Shin DS, Carrie, Duong David; Visualization: Park HN, Carrie; Writing: original draft: Park HN, Shin DS; Writing: review and editing: Park HN, Shin DS, Carrie, Duong David.

Funding

This work was supported by the Hallym university research fund [grant numbers HRF-201807-012].

Data availability

No datasets were generated or analysed during the current study.

Declarations

Ethics approval and consent to participate

Ethical approval and informed consent were not required for this study because it is a scoping review of previously published literature and did not involve any experiments on humans or animals. All procedures were conducted in accordance with relevant guidelines and regulations.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.