tb skin test after being vaccinated with bcg

Nurses Safety

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Specializes in PACU.

Is it okay to be tested for tb after you have been vaccinated with the bcg vaccine? Sorry if I posted this in the wrong section. New to the site!

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Specializes in ORTHOPAEDICS-CERTIFIED SINCE 89.

No point, you will always have a positive reaction. YOu should get a chest xray.

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Specializes in PACU.

Thanks for your reply...I read this online...

What if I’ve had BCG vaccine?

Even if you have had BCG vaccine, you can have a TB skin test.

• People who have had BCG vaccine still can get latent TB infection and active TB disease.

• BCG vaccine may help protect young children from getting very sick with TB. This protection goes away as people get older.

• BCG vaccine sometimes causes a positive TB skin test reaction. But if you have a positive reaction to the TB skin test, it probably is from TB germs in your body - not from your BCG vaccine.

Protect your health and the health of your family - get a TB skin test! To get a TB skin test, contact your doctor or your public health department.

You can have a TB skin test, even if you have had BCG vaccine!

Any thoughts?

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Specializes in Infusion Nursing, Home Health Infusion.

Sure you can still administer a TB skin test to someone who has had a BCG but if you have a significant induration (as in a positve reaction) a clinician will then need to look into further as in a CXR...obtain AFB ....ect

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Specializes in PACU.

Thanks for your reply! :)

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Specializes in Med/Surg, Ortho, ASC.

My TB certification classes have always taught that it is pointless and a waste of time to obtain a TB test if you have been given the BCG injection.

Just go straight to a standard CXR. It's the gold standard. My facility now requires it for anyone who tests positive on the PPD, BCG history or not.

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I have the same issue, and here's what I know from personal experience. Most of the people who had BCG vaccine will have exaggerated reaction mimicking TB infection. My family physician told me not to get any more skin tests, and just to have chest x-rays. Since 2005, there has been a new skin TB test, QuantiFERON®-TB Gold, but as far as I know, it is not widely used. This test can distinguish between tuberculosis antigens and tuberculosis infection. You may want to ask if your institution is willing to use this test.

Here's the link with more info about QuantiFERON®-TB Gold test:

http://www.cdc.gov/mmwr/preview/mmwrhtml/rr5415a4.htm

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Specializes in Emergency nursing.

BCG vaccination can cause a false positive reaction to a TB skin test (TST). The gold standard for a positive TST used to be a chest x-ray, then sputum cultures if indicated clinically. The drawback of using a CXR alone, is that the CXR cannot determine latent TB status. It will show evidence of active disease or damage from previous disease. Mycobacterium tuberculosis can remain dormant for a significant period before a person shows signs of an infection clinically. This is a latent TB infection (LTBI). In the last 5 years, two different blood tests have been developed that are being used to better determine a person's LTBI status. They have been shown to be more specific than a TST and can detect a LTBI. These two blood tests are Quantiferon TB Gold and the T-spot TB Test. A person who has a positive Quantiferon TB Gold or T-spot TB Test is considered to have a LTBI if there are no other clinical signs of TB present (including a negative CXR). Because of the specificity of the the two tests, a false positive is rare and is usually the result of improper draw technique, processing time, etc. Essentially, if you have a positive TST, but a negative Quantiferon or T-spot, it is safe to say that you are negative for TB. On college and university campuses where there is large scale TB testing for incoming international students, many have gone to using these blood tests, either exclusively or in conjunction with skin testing. However, I haven't seen as many healthcare facilities using it until recently. Before going back to the ER recently, I worked for the last 3 years in college health as the nurse manager for the student health center at a major university that did a significant amount of TB testing. We used both the skin test and the blood test in conjunction.

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Specializes in PACU.

Thanks for all your replies...I really appreciate the information. I've heard of the QuantiFERON®-TB Gold test and I will look into that further...My other question is besides the fact that it is pointless to receive a tb skin test after having been vaccinated with bcg, and that it will most likely cause a positive reaction...Are there any other adverse reactions that should be expected?

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Specializes in Emergency nursing.
Thanks for all your replies...I really appreciate the information. I've heard of the QuantiFERON®-TB Gold test and I will look into that further...My other question is besides the fact that it is pointless to receive a tb skin test after having been vaccinated with bcg, and that it will most likely cause a positive reaction...Are there any other adverse reactions that should be expected?

You can still have a TB skin test after BCG vaccination, just know that it can cause a false positive reaction. I have seen numerous cases where there was a history of BCG vaccination but the skin test was negative. One thing to consider about the blood testing is the cost. It is significantly more expensive than a skin test and you will have to see if your insurance will cover it. I know at my last facility, we charge $15 for a TB skin test and $75 for Quantiferon. The way I presented it to my patients was this: You can do the $15 test, just know that there is a possibility that you will end up needing the $75 if you have a positive reaction to the skin test. As far as adverse reactions, the most common reaction to a TB skin test is localized swelling, redness, itching at the injection site. Remember, that the result is determined by the size of the induration, not just redness. This is why they tell you not to scratch the injection site or cover it with a bandaid.

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Specializes in PACU.
You can still have a TB skin test after BCG vaccination, just know that it can cause a false positive reaction. I have seen numerous cases where there was a history of BCG vaccination but the skin test was negative. One thing to consider about the blood testing is the cost. It is significantly more expensive than a skin test and you will have to see if your insurance will cover it. I know at my last facility, we charge $15 for a TB skin test and $75 for Quantiferon. The way I presented it to my patients was this: You can do the $15 test, just know that there is a possibility that you will end up needing the $75 if you have a positive reaction to the skin test. As far as adverse reactions, the most common reaction to a TB skin test is localized swelling, redness, itching at the injection site. Remember, that the result is determined by the size of the induration, not just redness. This is why they tell you not to scratch the injection site or cover it with a bandaid.

Thanks for your reply! :yeah:

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I have the same issue... the health department in most states "REQUIRES" to get a ppd, regardless or not if you had the bcg. So what you do is you tell your healthcare provider that you have the BCG, get the ppd so they comply with the healthcare department, the test is likely to be a "false +", and then you get a chest x ray, I have gone through this every year since I moved to the states 6 years ago. I got 2 BCG vaccines, one when I was born and one when I was 12. I am 25 now and still to this day I have positive ppd tests. According to my primary care physican by now I should not test positive, but explained that inmmunity is different in everybody and I am still probablly immune to tb. My chest x rays are clear all the time.

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