How often should someone get a TB test?

  1. Hey Everyone,

    I was wondering if anyone could tell me how often I could get a TB test?
    Here's why I ask. I'm a recent graduate and just started working as a LPN, today was my first day on the new job actually.
    I was an aide at my old job (which was less than 2 weeks ago). I obviously had to get a TB test today for my new job. However, I received one about 2 weeks ago from my old job (just b/c I was due for it again). Now, I've NEVER had a positive TB test, but today after I get home from work, I look down and my arm is a little red and a little raised and I'm freaking out!
    Could I have somehow received the antibody for TB recently and not know it, could I just be having some kind of reaction that I've never had before, or is it possible that I had these two TB tests, too close together!?

    Please help
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    About Nurse Kel

    Joined: Oct '08; Posts: 2; Likes: 1


  3. by   just_cause
    The period of testing is normally based on your hospital (employers) standards/procedures. I do know many health care facilities require workers to pass a two step process for TB testing.
    I've take the ever so non scientific extract from wikepedia.
    When you go back to get your TB 'read' I would ensure you bring your testing info from your previous test- if you don't have it just tell them about it. Next step is likely a sample test that will be sent to the labs.

    Two-step testing

    Some people who were previously infected with TB may have a negative reaction when tested years after infection, as the immune system response may gradually wane. This initial skin test, though negative, may stimulate (boost) the body's ability to react to tuberculin in future tests. Thus, a positive reaction to a subsequent test may be misinterpreted as a new infection, when in fact it is the result of the boosted reaction to an old infection.
    Use two-step testing for initial skin testing of adults who will be retested periodically (e.g., health care workers). This ensures that any future positive tests can be interpreted as being caused by a new infection, rather than simply a reaction to an old infection.
    • Return to have first test read 48-72 hours after injection
    • If first test is positive, consider the person infected.
    • If first test is negative, give second test 1-3 weeks after first injection
    • Return to have second test read 48-72 hours after injection
    • If second test is positive, consider person previously infected
    • If second test is negative, consider person uninfected [6]
    A person who is diagnosed as "infected" on two-step testing is called a "tuberculin converter". The US recommendation that prior BCG-vaccination be ignored results in almost universal false diagnosis of tuberculosis infection in people who have had BCG (mostly foreign nationals). Please refer to the chapter on BCG for a discussion of boosting.
  4. by   pielęgniarka
    If the bump (induration) is 5 mm and you are at high risk it could require an x-ray follow up. Generally for low risk the induration (bump) has to be 10mm to be considered positive. The test is not read by the erythma (redness) from what I have learned.
    The place I'm working at now at requires a 2 step TB testing for all new hires and new admits. It's done annually. I had a tb test done within a week of eachother once, needed one for school and then needed another one for a job (job wouldn't take the school one). For the 2 steps, the 1st one given and read in 48-72 hrs. Next one given 10 days after that reading, in opposite forearm and f/u the same.
  5. by   christine_chapel
    If you just had your test administered today, you might have a little redness and raised area until the irritation from the injection subsides. What they look for is induration (hard and lumpy) at 48 to 72 hours. They don't look at it before 48 hours because plenty of people have irritation just from having a needle stuck in them. So no worries, it will probably get better over the next day.
  6. by   prmenrs
    What Chrisine said. Don't worry about it til it's done!
  7. by   PedsAtHeart
    I agree. We do TB test once a year and if you are late or never had one then you get a 2 step test, and those would be 7-10 days apart. As for the redness on your arm, that is common, doesnt mean you are positive. A lot of people have some small reactions to the medication. It is not read by the redness but by the size of the "lump" it makes, if any. I BELIEVE it has to be >15 mm to be considered positive, but the other poster could be correct in the 10 mm.
  8. by   Nurse Kel
    Thank you all for replying, you have all helped me to relax and understand what's going on, better!
    BTW: that mark is gone today and so you all were correct, there wasn't anything to worry about!

    I'm a panicker, can you tell! ha

    Thanks again!
  9. by   gloria1234
    what do you think about getting a tb skin test every 3 months? This hospital I have just started, give there ER a tb skin test every 3 months. I think it crazy! Knowing whats in it .