Accuracy of fecal immunochemical tests for colorectal cancer: systematic review and meta-analysis

Performance characteristics of fecal immunochemical tests (FITs) to screen for colorectal cancer (CRC) have been inconsistent. To synthesize data about the diagnostic accuracy of FITs for CRC and identify factors affecting its performance characteristics. Online databases, including MEDLINE and EMBASE, and bibliographies of included studies from 1996 to 2013. All studies evaluating the diagnostic accuracy of FITs for CRC in asymptomatic, average-risk adults. Two reviewers independently extracted data and critiqued study quality. Nineteen eligible studies were included and meta-analyzed. The pooled sensitivity, specificity, positive likelihood ratio, and negative likelihood ratio of FITs for CRC were 0.79 (95% CI, 0.69 to 0.86), 0.94 (CI, 0.92 to 0.95), 13.10 (CI, 10.49 to 16.35), 0.23 (CI, 0.15 to 0.33), respectively, with an overall diagnostic accuracy of 95% (CI, 93% to 97%). There was substantial heterogeneity between studies in both the pooled sensitivity and specificity estimates. Stratifying by cutoff value for a positive test result or removal of discontinued FIT brands resulted in homogeneous sensitivity estimates. Sensitivity for CRC improved with lower assay cutoff values for a positive test result (for example, 0.89 [CI, 0.80 to 0.95] at a cutoff value less than 20 µg/g vs. 0.70 [CI, 0.55 to 0.81] at cutoff values of 20 to 50 µg/g) but with a corresponding decrease in specificity. A single-sample FIT had similar sensitivity and specificity as several samples, independent of FIT brand. Only English-language articles were included. Lack of data prevented complete subgroup analyses by FIT brand. Fecal immunochemical tests are moderately sensitive, are highly specific, and have high overall diagnostic accuracy for detecting CRC. Diagnostic performance of FITs depends on the cutoff value for a positive test result. National Institute of Diabetes and Digestive and Kidney Diseases and National Cancer Institute.

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