# What is positive predictive value and negative predictive value?

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## What is the difference between PPV and sensitivity?

The Positive Predictive Value definition is similar to the sensitivity of a test and the two are often confused. However, PPV is useful for the patient, while sensitivity is more useful for the physician. Positive predictive value will tell you the odds of you having a disease if you have a positive result.

## What is the meaning of positive predictive value?

Listen to pronunciation. (PAH-zih-tiv preh-DIK-tiv VAL-yoo) The likelihood that an individual with a positive test result truly has the particular gene and/or disease in question. Also called PPV.

## What is a good PPV and NPV?

Positive predictive value (PPV) and negative predictive value (NPV) are directly related to prevalence and allow you to clinically say how likely it is a patient has a specific disease.

Negative predictive value (NPV)

Prevalence PPV NPV
20% 69% 97%
50% 90% 90%

## What is the meaning of negative predictive value?

Listen to pronunciation. (NEH-guh-tiv preh-DIK-tiv VAL-yoo) The likelihood that an individual with a negative test result is truly unaffected and/or does not have the particular gene mutation in question. Also called NPV.

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## How do you calculate NPV and PPV?

Positive Predictive Value (PPV) = 100xTP/(TP+FP) Negative Predictive Value (NPV) = 100xTN/(FN+TN)

## What is the difference between PPV and NPV?

PPV is the proportion of people with a positive test result who actually have the disease (a/a+b); NPV is the proportion of those with a negative result who do not have the disease (d/c+d).

## What does high negative predictive value mean?

The more sensitive a test, the less likely an individual with a negative test will have the disease and thus the greater the negative predictive value. The more specific the test, the less likely an individual with a positive test will be free from disease and the greater the positive predictive value.

## What does negative predictive value NPV refer to in diagnostic testing?

The negative predictive value is defined as the number of true negatives (people who test negative who don’t have a condition) divided by the total number of people who test negative. It varies with test sensitivity, test specificity, and disease prevalence.

## How do you calculate PPV?

For a mathematical explanation of this phenomenon, we can calculate the positive predictive value (PPV) as follows: PPV = (sensitivity x prevalence) / [ (sensitivity x prevalence) + ((1 – specificity) x (1 – prevalence)) ]