Spectrum bias

Initially identified in 1978, spectrum bias refers to evaluating the ability of a diagnostic test in a biased group of patients which leads to an overestimation of the sensitivity and specificity of the test. Examples are initial overestimates of the sensitivity and specificity of the carcinoembryonic antigen and urinary dipstick tests.

The inflated results can occur when the diagnostic test is compared in a healthy population versus a population with advanced disease.

If properly analyzed, recognition of heterogeneity of subgroups can lead to insights about the test's performance in varying populations.