RT Journal Article SR Electronic T1 Relations among sensitivity, specificity and predictive values of medical tests based on biomarkers JF General Psychiatry JO Gen Psych FD BMJ Publishing Group Ltd SP e100453 DO 10.1136/gpsych-2020-100453 VO 34 IS 2 A1 Hongyue Wang A1 Bokai Wang A1 Xunan Zhang A1 Changyong Feng YR 2021 UL http://gpsych.bmj.com/content/34/2/e100453.abstract AB Diagnostic tests are usually based on some quantitative biomarkers. Two key parameters used to characterise the quality of a test are test sensitivity and specificity. Predictive values of the disease status based on test results are also of interest in medical research and public health management. In this paper, we study the relations among sensitivity, specificity and predictive values of the test. The core concept is risk function, which is assumed to be an increasing function of the biomarker. Our results show that test sensitivity and specificity change in opposite directions. The positive predictive value and the sensitivity also change in opposite directions. Likewise, the negative predictive value and the specificity change in opposite directions.