How trustworthy is a positive HIV test result? How probable is an actual infection when the test is positive? Even professionals often get such questions wrong, which can lead to misdiagnoses and unnecessary surgeries. How trustworthy is a positive HIV test result? How probable is an actual infection when the test is positive? Even professionals often get such questions wrong, which can lead to misdiagnoses and unnecessary surgeries. Mathematics Education Phys.org – latest science and technology news stories