Table 2.

NLR Ratio in Various Studies.^58–86

Authors	Study Group	Control Group	NLR Values		P value	Cut-off	AUC	Specificity (%)	Sensitivity (%)	Observations
	N	N	Study	Control
Sayed et al68	n=701; ICU n=41 non-ICU n=660	n =250	Non-ICU=2.85 ICU=5.5	2.18	<0.0001	5.5	-	23.65	96.4	NLR in connection with history-talking and physical examination may be useful in ruling out the infection. NLR can be an independent prognostic factor of a severe infection. Patients with high NLR should be closely monitored and managed.
Pirsalehi et al69	n=243; ICU n=59 Death n=184	Mild and moderate n=1077	8.17 ICU=9.23 Death=5.3	4.45	<0.0001	-	-	-	-	NLR >6.5 may reflect the progression of the disease towards an unfavorable clinical outcome. NLR > 9 may be a strong death predictor.
Maddani et al 202158	n=50	n=142	8.45	2.32	<0.001	5.2	0.91	-	-	Higher incidence of severe disease is observed in older individuals, male, patients with diabetes mellitus, and increased inflammatory parameters such as NLR. NLR is an independent predictor of disease severity. NLR may be useful in identification high-risk patients at resource-limited settings and refer them to tertiary care centers for better outcome.
Jain et al70	n=29 Severe	n=162 Non-severe	7.41	3.3	<0.001	4.1	0.779	78	69	NLR is significantly higher in severe COVID-19 patients than non-severe patients. NLR shows a diagnostic utility in differentiation severe and non-severe cases COVID-19.
Toori et al 202171	n=169 Symptomatic: Mild n=96, Moderate n=33, severe n=40	n=551 Asymptomatic	Mild=2.08 Moderate=4.79 Severe=9.9	1.92	<0.0001	-	-	-	-	NLR is an effective marker to predict and stratify COVID-19 patients as per severity and effectivity.
Moradi et al 202172	Severe n=142	Non-severe n=77	5.0	4.1	0.008	-	-	-	-	NLR can be a predictor of survival in COVID-19 patients.
Erdogan et al 202173	Severe n=36	Non-severe n=268	4.85	2.2	<0.0001	-	-	-	-	NLR is significantly higher in severe COVID-19 patients, supporting the fact that it can be a prognostic biomarker.
Yan et al 202059	Non-survivors n=40	Survivors n=964	49.06	4.11	0.001	11.75	0.945	78.1	97.5	High NLR is associated with poor outcome in critically ill patients with COVID-19. NLR is an independent risk factor for predicting in-hospital all-cause mortality in COVID-19 patients. NLR may be used as a surrogate marker of disease severity at the patient’s admission.
Seyit et al 202074	Sars-COV-2 Positive n=110	Sars-COV-2 Negative n=123	2.42	1.87	0.007	1.81	0.615	46	70	NLR is significantly higher in COVID-19 positive patients than in negative.
Eslamijouybari et al 202075	n=520 Cured n=422, Died n=98	n=527	Cured=3.45 Death=6.55	1.56	0.0001	-	0.703	-	-	NLR is associated with disease severity and is higher in severe cases of the disease.
Singh et al76	Severe n=93	Non-severe n=108	10.8	7.36	0.0001	-	0.6	60	55	NLR calculated at the time of patient’s admission has a high predictive value for disease deterioration and adverse clinical outcome. NLR can be used for early stratification of patients.
	Non-survivors n=91	Survivors n=110	13.15	9.72	0.01	-	-	-	-
Wang et al 202060	Non-survivors n=12	Survivors n=119	13.87	1.95		3.338	0.963	84	100	NLR is a biomarker reflecting the presence of systematic inflammation, and is associated with all-cause mortality in COVID-19. NLR increase is a useful biomarker to predict the mortality in COVID-19.
Qin et al 202083	Severe n=286	Non-severe n=166	5.5	3.2	<0.0001	-	-	-	-	NLR may be helpful in the early screening of critical illness, diagnosis and treatment of COVID-19.
Bastug et al62	ICU n=46	Non-ICU n=145	9.04	2.41	<0.001	≥3.21	0.861	62.8	84.4	NLR increase seems to be the most powerful laboratory predictor of severe prognosis for COVID-19 and may assist clinicians to identify and follow-up patients with higher risk for progression.
Ertekin et al 202161	Died n=220	Survivors n=280	35.43	6.75	<0.001	≥12.1	0.930	84.4	90.9	NLR could be a useful predictive parameter for COVID-19 patients.
Chen et al 202077	Non-survivors n=104	Survivors n=577	12.27	3.338	0.000	>6.66	-	-	-	The combination of NLR and acute myocardial injury on admission is a highly predictive for mortality and survival exclusion diagnosis. NLR >6.66 and myocardial injury require a more aggressive treatment strategy. NLR predicts mortality better than age, LDH, CRP, and lymphocyte levels, suggesting it may be the best predictive parameter (p<0.05).
Bilge et al 202166	Cancers n=75	No cancers n=111	7.02	5.52	NS	-	-	-	-	There are no significant differences in NLR value between the two compared groups in this study.
Waris et al 202190	Mild n=52 Moderate n=24 Severe n=9 Critical n=16		Mild=2.7 Moderate=4.95 Severe=5.11 Critical=6.87		<0.001	-	-	-	-	NLR may be helpful for clinicians to identify potentially severe cases at early stages, initiate effective management in time, and conduct early triage which may reduce the overall mortality of COVID-19 patients.
Zhao et al 202063	Severe n=74	Mild n=211	4.32	2.89	<0.001	3.41	0.76	-	-	NLR reflects the intensity of inflammation and is associated with severity of patients with COVID-19. NLR is more useful to predict the severity COVID-19 than other inflammatory markers.
Gujar et al 202164	ICU n=264	Isolation n=577	10.9	2.9	0.001	3.6	0.86	-	-	NLR can predicts severe illness with high accuracy.
López-Escobar et al 202178	Non-survivors n=321	Survivors n=1767	8.7	3.8	<0.0001	6.63	-	74	62	NLR is usefulness as a prognostic marker of inflammation in patients who died due to COVID-19.
Velazquez et al 202179	ICU n=185	Non-ICU n=2069	6.9	4.1	<0.0001	4.93	-	58	68	Patients requiring ICU admission have significantly higher NLR value at the time of hospital admission compared to patients not requiring ICU admission. Higher values of NLR are associated with ICU entry only for strata with SaO2 > 90%, male sex and age < 70 years.
Acar et al 202065	Non-survivors n=19	Survivors n=129	21.0	9.4	≤0.05	10.9	0.816	76.7	73.6	NLR is associated with disease mortality and can be used to predict disease progression and mortality. NLR reflects intensity of inflammation and also indicates a poor prognosis.
Ramos-Penafiel et al 202067	Death n=54	Alive n=71	13.93	10.56	0.052	-	-	-	-	NLR can predicts SARS-CoV-2 infection-associated mortality.
Kilercik et al 202180	Critical-survivors severe n=23 Critical non-survivors; death n=15	Non-critical mild n=59	Critical-survivors severe=6.2 Critical non-survivors; death=11.4	Non-critical Mild= 2.67	<0.001	3.1	-	54.1	87	NLR is the best time-related marker over the course of the disease, distinguishing non-critical patient group from non-survivor patient group after the 2th-4th day of admission NLR can be used as an indicator to distinguish critical patients from non-critical COVID-19 patients and to predict mortality from COVID-19.
						4.4	-	68.2	78.5
Citu et al 202281	Deaths n=17	Survivors n=91	13.83	8.31	0.001	9.1	0.689	67	70	NLR determined at hospital admission have a high value in predicting mortality in patients with COVID-19.
Moisa et al 202182	Group 1 -patients on IMV upon ICU admission n=33 group −2 IMV during ICU-LOS n=134 Group 3 - non-IMV during ICU-LOS n=105		G1=22.76 G2=22.46 G3=8.95		<0.0001	-	-	-	-	NLR is the best independent predictor for invasive mechanical ventilation need and death.
	Non-survivors n=142	Survivors n=130	24.4	9.5	<0.0001	-	-	-	-
Fois et al 202086	Non-survivors n=29	Survivors n=90	9.17	5.00	0.0015	15.2	0.697	97	38	NLR increases in severe COVID-19 disease patients and is associated with disease severity. NLR have a high value in predicting disease severity. NLR is also associated with survival.

Abbreviations: ICU, intensive care unit patients; non-ICU, non-Intensive care unit patients; IMV, invasive mechanical ventilation; ICU-LOS, ICU length of stay.