Background: Infection markers such as the C-reactive protein (CRP) can be used in addition to the clinical diagnosis of an infectious disease. So far, CRP tests have been carried out in the laboratory; CRP "point-of-care-testing" (POCT) refers to measurements close to the patient in primary care. The result is available within minutes. CRP POCT is intended to assist the physician to rule out a severe bacterial infection and support a decision on the need for antibiotic prescription.

Methods: Three systematic literature searches were carried out in different databases: Clinical efficacy and safety (SR1), accuracy of diagnostic tests (SR2) and analytical performance (SR3).

Results: The systematic review of clinical efficacy and safety (SR1) included twelve studies. Seven RCTs with 5,320 patients were included in the meta-analysis for the primary endpoint of prescription (antibiotic prescription at initial consultation i.e. index consultation). The pooled estimate of the RCTs showed a statistically significant reduction in antibiotic prescription at initial consultation in the CRP POCT group compared to standard care (relative risk [RR] 0.76, 95% confidence interval [CI]: 0.67-0.86, I2= 70%). For the accuracy of the diagnostic tests (DTA) (SR2), 15 (highly heterogeneous) studies were identified concerning differences in the criteria used to define a positive test (threshold values), the diagnostic criteria (including the use of CRP values alone or as part of a clinical algorithm), the patient populations and the lack of a universal reference standard for the diagnosis of acute respiratory infections requiring antibiotics. The systematic review of analytical performance was based on 18 studies (SR3). Analytical performance describes the ability of the assay to accurately measure CRP values within an "acceptable" bias (the difference between the measured value and the true value). An acceptable bias of max 15% could be found for some tests.

Conclusion: Studies suggest that the use of CRP POCT leads to a statistically significant reduction in the number of patients who present themselves with acute respiratory infections in primary care and receive a prescription for an antibiotic at the initial consultation.