Skip to main content

Table 1 Measures of diagnostic and analytical performance

From: Methodological challenges in appraising evidence on diagnostic testing for WHO guidelines on hepatitis B and hepatitis C virus infection

Diagnostic/clinical accuracy The ability of a diagnostic test/assay to correctly identify those with the infection or disease of interest and those without the infection or disease.
 • Sensitivity The ability of a test to correctly identify those with the infection or disease (i.e. true positives/true positives + false negatives).
 • Specificity The ability of a test/ assay to correctly identify the absence of the disease (i.e. true negatives/true negatives + false positives).
 • Positive predictive value The probability that when the test result is positive, the infection/disease is truly present (i.e. true positives/true positives + false positives). Predictive values are influenced by the prevalence of the disease in the population being tested.
 • Negative predictive value The probability that when the test result is negative, the infection/disease is truly absent (i.e. true negatives/true negatives + false negatives).
Analytical performance The reliability and accuracy of a test/assay for measuring what it seeks to measure.
 • Linearity The degree to which the results of a test/assay are directly proportional to the amount of analyte.
 • Limit of detection (LoD) The lowest amount of an analyte that a test/assay can consistently distinguish from absence of the substance.
 • Lower limit of quantification (LoQ) The lowest amount of an analyte that a test/assay can consistently quantify.
 • Precision The degree to which repeated measures of an analyte by a test/assay under the same conditions provide the same results.
  1. Adapted from World Health Organization Guidelines on Hepatitis B and C Testing, 2017, Glossary of Terms [3]