Negative predictive value
Citation, DOI & article data
Negative predictive value of a test/investigation is defined as the proportion of patients with negative results being truly disease free.
Negative predictive value = true negatives detected / total negative results
(where "total negative results" = true negative + false negative)
One can also determine the NPV with an estimate of sensitivity, specificity, and pretest probability (p).
NPV = [(specificity) x (1 - p)] / [specificity x (1 - p) + (1 - sensitivity) x (p)]
- unlike sensitivity and specificity, NPV is highly dependent on the prevalence of the disease in the target population
- 1. Parikh R, Mathai A, Parikh S et-al. Understanding and using sensitivity, specificity and predictive values. Indian J Ophthalmol. 2008;56 (1): 45-50. Free text at pubmed - Pubmed citation
- 2. Weinstein S, Obuchowski NA, Lieber ML. Clinical evaluation of diagnostic tests. AJR Am J Roentgenol. 2005;184 (1): 14-9. doi:10.2214/ajr.184.1.01840014 - Pubmed citation