Your activity: 19 p.v.
your limit has been reached. plz Donate us to allow your ip full access, Email: sshnevis@outlook.com

Calculator: Post-test probability from pre-test probability, sensitivity, and specificity


Calculator: Post-test probability from pre-test probability, sensitivity, and specificity

 
Input
 
Pre-test probability  
Sensitivity  
Specificity  

 
Results
 
Important: Inputs must be complete to perform calculation.

 
 
Post-test probability of positive result  
Post-test probability of negative result  
 
Decimal precision  

 
 

 
Notes
  • Post-test probability of positive result is the probability that the disease is present when the test result is positive.
  • Post-test probability of negative result is the probability that the disease is present when the test result is negative.
  • Pre-test probability is usually equivalent to the prevalence of a disease or finding in a particular population.

 
Equations used
 
Post_Odds_Pos = (Pre-test probability * Sensitivity) / ((1 - Pre-test probability) * (1-Specificity))
Post-test probability of positive result = Post_Odds_Pos / (1 + Post_Odds_Pos)
Post_Odds_Neg = (Pre-test probability * (1-Sensitivity)) / ((1-Pre-test probability) * Specificity)
Post-test probability of negative result = Post_Odds_Neg / (1 + Post_Odds_Neg)

 

 
References
  1. Brown DD, LeBlond RF, DeGowin RL. Principles of diagnostic testing. In: DeGowin’s Diagnostic Examination, 9th ed, McGraw-Hill Professional, 2009. p.798.
  2. Perera R, Heneghan C. Making sense of diagnostic test likelihood ratios. ACP J Club 2007; 146:A8.
Only digits 0 to 9 and a single decimal point (".") are acceptable as numeric inputs. Attempted input of other characters into a numeric field may lead to an incorrect result.

Information on this page may not appear correctly if printed.

Legal Notices and Disclaimer

All information contained in and produced by the EBMcalc system is provided for educational purposes only. This information should not be used for the diagnosis or treatment of any health problem or disease. THIS INFORMATION IS NOT INTENDED TO REPLACE CLINICAL JUDGMENT OR GUIDE INDIVIDUAL PATIENT CARE IN ANY MANNER. Click here for full notice and disclaimer.

EBMcalc is Copyright © 1998-2023 Foundation Internet Services, LLC

Topic 13436 Version 7.0