Positive Predictive Value and Test Threshold

[HTwrestler112]

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It was my understanding from class that positive predictive value was determined by the prevalence of the disease in the population and the characteristics of the test/disease, not by the arbitrarily decided "test threshold," but UWorld just asked a question in which moving the test threshold a less stringent level decreased the positive predictive value.

This does not agree with my understanding of PPV. Can anyone explain, confirm, or refute?

 

[loveoforganic2]

Think about it logically. PPV is how likely a positive test is to represent an individual w/dz. If you decrease the threshold, you increase the false positive rate and decrease the PPV