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Positive predictive value

Dr Matt A. Morgan and Dr Ayush Goel et al.

Positive predictive value of a test/investigation is defined as the proportion of patients with positive results being truly diseased.


Positive predictive value = true positives (TP) detected / total positive results

(total positive results = true positive (TP) + false positive (FP)

Bayes' theorem

One can also determine the PPV with an estimate of sensitivity, specificity, and pretest probability (p).

PPV = [(sensitivity) x (p)] / [sensitivity x (p) + (1 - specificity) x (1 - p)]

Practical points

  • unlike sensitivity and specificity, PPV is highly dependent on the prevalence of the disease in the target population

Article information

rID: 31423
Synonyms or Alternate Spellings:
  • PPV

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Cases and figures

  • Derivations of se...
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