Research on point-of-care tests in outpatient care in Germany: A scoping review and definition of relevant endpoints in evaluation studies

Background: The fast turnaround time and user-friendliness of point-of-care tests (POCTs) offer a great potential to improve outpatient health care where clinical decisions have to be made during the physician-patient encounter and time resources are limited. The aim of this scoping review is to describe the extent and nature as well as gaps in German research activities on POCT in outpatient care. In addition, we define research endpoints that should be addressed in the comprehensive evaluation of POCTs targeted for outpatient care. Methods: We performed a scoping review with a systematic literature search in Medline (via PubMed), Scopus, Web of Science, Cochrane library and Google Scholar for German publications on POCT with relevance to German outpatient care published from January 2005 to November 2020. Results: Our literature search identified 2,200 unique records. After literature selection 117 articles were included in this scoping review. Just over half of the articles (67/117, 57.3%) were primary research studies with original data, while one third of all the studies (33.3%) were secondary research articles (e.g., review articles). The remaining articles were clinical recommendations / position papers (7/117, 6.0%) and other types of articles (3.4%). The majority of articles focused on POCT use in infectious diseases (44/117, 37.6%), diabetic syndromes (15.4%), cardiac disease (12.0%) or coagulopathies and thrombosis (10.3%), while the remaining articles did not specify the disease (13.7%) or investigated other diseases (11.1%). Similar to international studies, most primary research studies investigated the diagnostic performance of POCT (e.g., sensitivity, specificity). Evidence beyond diagnostic accuracy remains scarce, such as the impact on therapeutic decisions and practice routines, clinical effectiveness, and user perspectives. In line with this, interventional studies (such as RCTs) on the effectiveness of POCT use in German outpatient care are limited. We define six endpoint domains that should be addressed in the evaluation of POCTs targeted for outpatient care: (i) diagnostic performance, (ii) clinical performance, (iii) time and costs, (iv) impact on clinical routines / processes, (v) perspectives of medical professionals and patients, and (vi) broader aspects. Conclusion: There is considerable research activity on POCTs targeted for use in outpatient care in Germany. Data on their potential benefits beyond diagnostic accuracy is often lacking and should be addressed in future POCT research studies.