Table 1.

SPIDER Tool Domains and descriptions of eligibility criteria for each domain.

SPIDER tool domain	Description of criteria
Sample	The participants of the studies were HCPs. These studies investigated the knowledge and views of the participants about direct-to-consumer genetic testing (DTC-GT). The HCPs were comprised of healthcare staff that could potentially provide direct healthcare services to the consumer. Examples of these HCPs included primary care physicians and general practitioners, specialists (e.g. clinical geneticists (CGs) or specialist physicians) and nurses and genetic counsellors (GCs). During the screening phase, the following HCPs were also identified: physician assistants, nurse practitioners and various other specialists (urologists, psychiatrists, and neurologists, etc.). Any studies related to non-clinical members such as scientists or laboratory staff members were excluded. However, one included paper’s participant group was comprised of 30% researchers [13]. Since more than half of the participants were GCs in this study, a decision was made to include it in this review [13]. Furthermore, studies were excluded if they related to only consumers or patients.
Phenomenon of Interest	The focus of this review was DTC-GT. Therefore, studies about any commercially available tests related to screening for various health issues and diseases were included. Examples of these tests are those that screen for cardiovascular risk or specific diseases such as breast cancer or Alzheimer’s disease. Papers were excluded if they were related to: DTC marketing or advertising as their focus; DTC ancestry testing; Genomic sequencing; Nutrigenetics or sports nutrigenomics; Paternity testing, prenatal carrier testing and other related reproductive health screening tests; Pharmacogenomics (since these tests assess the genetic predisposition of how someone metabolises certain medications and not their predisposition to a disease or illness); Any genetic testing that was not directly available to the consumer. Pharmacogenetic testing was regarded to be qualitatively different from DTC-GT for disease risk, as they generally only have applicability with the involvement of a health professional (i.e. initiating/altering a current medication). Furthermore, issues such as psychological distress, the need for genetic counselling, and potential for discrimination do not apply or apply to a lesser extent compared to other types of DTC-GT.
Design	Primary research papers that were published and contained data pertaining to the knowledge and views of HCPs about DTC-GT were included. Clinical trial registry searches were not included as it was unlikely that searches on these platforms would yield any applicable studies. An ad hoc search on ClinicalTrials.gov with the search term ‘direct-to-consumer genetic testing’ did not produce any relevant studies [14]. The following study designs were included in this review: Any type of survey or questionnaire; Studies involving focus groups; Studies involving interviews. Letters, editorials, opinions, commentaries, and conference papers were excluded from this review. Systematic reviews relevant to DTC-GT were excluded for the purposes of this review. The reference lists of these systematic reviews were searched so that relevant primary studies could be identified.
Evaluation	HCPs’ views and experiences of DTC-GT were evaluated. Studies were included if they described any of the following aspects on DTC-GT: views, perceptions, attitudes, knowledge, experiences, opinions, beliefs, feelings, perspectives, and awareness.
Research Type	This review included types of research that were either qualitative, quantitative or mixed methods [12].