PPD ERROR???

[ShanNurse87]

i recently got a ppd done on a thursday for a new job. i was unable to get it read in the 48 to 72 hour period. So at the start of my new job, i got another one, and it's been a couple hours, and i already see a positive result. i am 100 percent sure i was never exposed to TB. could this be a error? Will the result disappear in a day?? Any input would be lovely. Thanks :)

[kathy313]

I'd worry if it showed positive in 48 hours, not a few. Sometimes the way people stick can leave a bruise or a bump.

[nurse2be2010]

Just curious if you are a nurse? The whole purpose of waiting the 48-72 hours to get the results read is because you may at first show a sign of a positive test but it will disapear if you have not been exposed. I am pretty sure health care workers will have a positive test if the RAISED "bump" is 10mm.. This usally doesnt include the redness that may surround it. Immunocompromised peopple (for example HIV/AIDS patients) will be considered positive if the raised "bump" is at least 5mm.

I would tell them that you were recently exposed to a PPD test not long ago to see what their specific policy is.

[cherrybreeze, ADN, RN]

What exactly are you seeing?

If it IS in fact positive (which would be indicated by a 10mm induration, in an otherwise healthy person), it wouldn't be an error...a false negative would be more probable than a false positive, and neither are likely.

[cherrybreeze, ADN, RN]

Just curious if you are a nurse? The whole purpose of waiting the 48-72 hours to get the results read is because you may at first show a sign of a positive test but it will disapear if you have not been exposed. I am pretty sure health care workers will have a positive test if the RAISED "bump" is 10mm.. This usally doesnt include the redness that may surround it. Immunocompromised peopple (for example HIV/AIDS patients) will be considered positive if the raised "bump" is at least 5mm.

I would tell them that you were recently exposed to a PPD test not long ago to see what their specific policy is.

I don't think having another recent test would be significant. I've had to have one repeated in the past because I forgot to have it read in time (couldn't see anything on my arm, so I forgot it was there!). It shouldn't affect the results of the current test.

[bjaeram]

Anything you see in the first few hours means nothing. It is only positive if it is positive in the window to get it read. They often appear positive at first and it goes away. Don't worry about it.

[traumalover, RN]

I've been a nurse for seven years and have my TB test read by our employee health nurse. I have heard that a recent test within 1 week of second one can cause a false positive, and then it is 10mm inguration. But honestly, I work ICU and always have and I really don't know squat about PPDs!

[traumalover, RN]

induration, not inguaration, sorry can't type

[aura_of_laura]

I give several hundred of these things a year... If it's positive (which I'd leave to the EH nurse to decide), then you've probably been exposed to TB.

If it is positive, don't start fretting! Close to 20% of employees I screen have a history of + PPD tests- it's pretty common in healthcare, even if you don't travel or work with TB patients. Just means you have to get a chest x-ray and usually do some annual screenings instead of a PPD.