The negative predictive value (NPV) of a diagnostic test is the proportion of those testing negative and are truly disease free. The more sensitive a test, the less likely it is that a negative result will be a true positive - and hence the higher the negative predictive value. The higher the negative predictive value, the higher the likelihood that a person tested negative truly is disease free. A high prevalence of the disease or condition tested for in the population decreases the NPV.