Positive predictive value

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

Calculation

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

Share article

Article Information

rID: 31423
Synonyms or Alternate Spellings:
  • PPV

Support Radiopaedia and see fewer ads

Cases and Figures

  • Drag
    Derivations of se...
    Figure 1
    Drag here to reorder.
  • Updating… Please wait.
    Loadinganimation

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.