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How long between PPD tests?
For a medical training program I'm applying to, I'm required to have 2 successive negative PPD tests. The school says the second test MUST be no more than 2 weeks after the first, but that it is fine if I get the second test immediately after the first is read. But the injection clinic says that after a negative first test, normally you wait a week to have a second PPD. What is the reason for waiting a week? Is there any reason why the second PPD cannot be done on the same day that the first test is read (72 hours after the first test was administered)?
3 Answers
- ?Lv 410 years agoFavorite Answer
The purpose of two tests is to catch people who have a low level of antibody. The benefit of waiting 1 week is for the body to have time to make more antibody- if it is going to.
If you can wait the week, it can help ensure that you are truly negative - or positive. Technically the second test *can* be placed as the first one is read but it is not ideal.
Source(s): work in healthcare - 6 years ago
The first injection is administered and read 48-72 hours later. Then the second injection is administered seven days after the first injection was given and read within 48-72 hours.
