February, 2003
© 2000, 2001, 2003 Scott S. Emerson, M.D., Ph.D.
Diagnostic Testing: 7
Diagnostic Testing: Example
VDRL in diagnosing syphilis: High sensitivity and high specificity
Sensitivity of test: Probability of positive in diseased
·90% of subjects with syphilis test positive
·(Actually depends on duration of infection)
·
Specificity of test: Probability of negative in healthy
·98% of subjects without syphilis test negative
·(Actually depends on age and prevalence of certain other diseases)