Published
If a person keeps receiving PPD skin tests and continues to have negative reactions to them, there's no harm in this. She can only continue to receive PPD skin tests if the results are always negative.
However, if a person has ever had one positive PPD skin test, it is strongly recommended that he/she never undergo another skin test again. This is because the positive reaction becomes stronger with each repeated skin test in a person who has already been exposed to the TB mycobacterium. Therefore, your friend might want to get chest x-rays from this point forward if she has had at least one positive skin test.
This is according to the NIH:
Risks
"There is a very small risk of severe redness and swelling of the arm in people who have had a previous positive PPD test and who have the test again. There also have been a few cases of this reaction in people who have not been tested before."
Source: http://www.nlm.nih.gov/medlineplus/ency/article/003839.htm
dblpn
385 Posts
A friend of mine a cna was talking to me about her ppd. in january she had a ppd and she recently had a ppd done a few weeks ago for another job but she lost the results and wanted to know if having another ppd will do anything to her. i told her i wasn't sure. her employer does a 2 step ppd for employees. is this something she should be concerned about?