Published October 2000

Diagnostic Test Statistics
Test Characteristics
  • Sensitivity: How good the test is at detecting disease
  • Specificity: How good the test is at identifying normal
  • Positive predictive value: How often a patient with a positive test has the disease
  • Negative predictive value: How often a patient with a negative test does not have the disease
Instructions: There are two methods to calculate the diagnostic statistics.

Enter the number of true positives, true negatives, false positives, and false negatives and press the Calculate Statistics button,

Or, Enter the total (number), prevalence (%), sensitivity (%) and specificity (%) and press the Calculate Table button.
Note: (95% Confidence Interval calculated with Binomial expansion)
Disease or Condition
Diseased
No Disease
Totals
Test Positive
Positive Predictive Value
Test Negative
Negative Predictive Value
Totals
Prevalence
Sensitivity
Specificity
Likelihood Ratio Positive Test
Likelihood Ratio Negative Test

References

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Dodd JD, MacEneaney PM, Malone DE. Evidence-based radiology: how to quickly assess the validity and strength of publications in the diagnostic radiology literature. Eur Radiol 2004; 14:915-922.
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Kelly S, Berry E, Roderick P, et al. The identification of bias in studies of the diagnostic performance of imaging modalities. Br J Radiol 1997; 70:1028-1035.
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Maceneaney PM, Malone DE. The meaning of diagnostic test results: a spreadsheet for swift data analysis. Clin Radiol 2000; 55:227-235.
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Simel DL, Samsa GP, Matchar DB. Likelihood ratios with confidence: sample size estimation for diagnostic test studies. J Clin Epidemiol 1991; 44:763-770.
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