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Diagnostic test evaluation calculator

Instructions: enter the number of cases in the diseased group that test positive (a) and negative (b); and the number of cases in the non-diseased group that test positive (c) and negative (d).

Next click the Test button.

Diagnostic test evaluation calculator
TestPresentn AbsentnTotal
PositiveTrue Positive a=
False Positive c=
a + c
NegativeFalse Negative b=
True Negative d=
b + d
Total a + b   c + d  


Statistic Formula Value 95% CI
Sensitivity Sensitivity  
Specificity Specificity  
Positive Likelihood Ratio Positive Likelihood Ratio  
Negative Likelihood Ratio Negative Likelihood Ratio  
Disease prevalence Prevalence  (*) 
Positive Predictive Value Positive Predicitive Value  (*) 
Negative Predictive Value Negative Predicitive Value  (*) 
Accuracy Accuracy  (*) 

See Help for computational details and interpretation.

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