Adherence to recommended blood-based screening tests for cancer and chronic diseases: A systematic literature review

Introduction: Blood-based tests represent a compelling option for early detection and management of cancers and other chronic diseases. While they may increase patient engagement, assumptions about greater adherence in clinical practice need further evaluation. This systematic review aimed to evaluate real-world adherence to established blood-based tests for commonly recommended screening indications to inform expectations for average-risk colorectal cancer (CRC) screening. Methods: A comprehensive and systematic search of PubMed, Embase, and citations was conducted to identify literature published from 2010 to 2023. Included studies examined adherence to United States Preventive Services Task Force (USPSTF) grade A/B blood test recommendations for type 2 diabetes, dyslipidemia, hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Prostate-specific antigen (PSA) testing adherence for prostate cancer screening (grade C USPSTF recommendation), the only widely accessible blood-based single-cancer screening test for average-risk adults, was also included. Studies without venipuncture-derived blood were excluded. Results: Of 53,067 articles, 69 were included. Adherence rates of blood-based screening tests were highly variable, with median values and interquartile range (IQR) of 66.3 % (59.2–71.1), 67.8 % (54.4–72.4), 34 % (21.9–50.5), and 36.8 % (29.1–59.1) for diabetes, dyslipidemia, HCV, and HIV, respectively. PSA testing adherence was 37.2 % (30–48.5). Information and selection bias were common risks of bias. Conclusions: Real-world adherence to recommended blood-based screening is suboptimal. Future research is needed to determine whether these findings are generalizable to blood-based CRC screening and to assess how such a strategy could impact clinical, economic, and health equity outcomes.