A gastroenterology research team is evaluating a novel non-invasive breath test for the detection of early-stage liver cirrhosis. The gold standard for confirming the diagnosis is a liver biopsy. The researchers conduct a study involving adult patients with chronic liver disease.
The results of the study are as follows:
- Liver biopsy confirms early-stage cirrhosis in patients.
- Among these patients, have a positive breath test.
- Among the patients without cirrhosis on biopsy, have a positive breath test.
What is the positive predictive value of the novel breath test in this study cohort? Provide your answer as a whole number percentage.
Answer: 75 %
Answer
75
The positive predictive value (PPV) is calculated by dividing the number of true positive results by the total number of positive test results (true positives + false positives). In this study, there are 180 true positives and 60 false positives. Thus, the total number of positive tests is 240. The PPV is calculated as 180 / 240 = 0.75, which translates to 75%.
Step-by-Step Solution
Key Concept
Positive predictive value (PPV) is the probability that a patient with a positive test result actually has the disease. It is calculated as True Positives / (True Positives + False Positives).
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