Why choose a 2-step TB skin test vs. TB blood test?

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For anyone who has had a TST (TB skin test), I am curious what advantages a TST test has over an IGRA (TB blood test).

It seems like, in general, TB skin tests are more painful than a blood draw (although many people don't experience too much pain). A person needs two skin injections (for a 2-step test), as opposed to one blood draw.

There are also more side effects for a TB skin test, such as blistering, itchiness, and a risk for allergic reaction (many places require epinephrine available just in case). Although those side effects doesn't happen to everyone, it seems much more likely than a side effect to a blood draw.

The IGRA is generally more accurate than TB skin testing, and the test can be completed in one visit, instead of four. Many studies have shown IGRAs to be more cost-effective long-term for employers.

I know many people don't find two skin tests to be a big deal, but I am interested in why a person would choose two skin tests over one blood draw. The CDC has stated the two are always interchangeable, and I am not aware of any place that only accepts skin tests (even if they don't mention the other options). If an employer or health insurance is paying, why do people choose a 2-step skin test?

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Specializes in OR, Nursing Professional Development.

My facility's lab doesn't do IGRA testing- we have to send them out to a contracted lab. PPDs are actually much cheaper in this scenario- line everyone up and stick them, then two days later line everyone up and read them. We don't have a choice over which test we get- by default, we get the PPD. The only other option offered is a chest x-ray. For patients, I've seen all of 1 get a Quantiferon Gold test.

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Specializes in EMS, ED, Trauma, CEN, CPEN, TCRN.

My government job does the two-step because it's cheaper; they don't offer the IGRA. My current non-gov hospital does the IGRA. I prefer getting my blood drawn!

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Specializes in Case mgmt., rehab, (CRRN), LTC & psych.

The TB blood test (Quantiferon Gold) is grossly expensive compared to the two-step tuberculin skin test. Therefore, the advantage of tuberculin skin testing (at least for the entity who pays) is its significantly lower cost.

The blood test is often reserved for those who have had a positive tuberculin skin test result and are unwilling to undergo chest x-ray imaging.

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I needed a test done when I was in nursing school for clinicals last year. My doc insisted on the blood test...I got stuck with the difference in cost. He said he felt it was more accurate but I feel the skin test would have been fine since I don't have any conditions that would result in a false negative.

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Specializes in NICU, PICU, educator.

Cost is a big factor. If you have just an RN staff of 900 that is a huge chunk of

money. Now, if the facility is paying for it and not out of my pocket, fine.

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Specializes in Nurse Scientist-Research.

Cost. My employee should pay for one for me because my PPD is +, but I have a hx of getting BCG. They say the effects should be long gone, but. . . So they just ignore the situation and as long as they leave me alone, I won't fuss too much!

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Specializes in orthopedic/trauma, Informatics, diabetes.

When I applied to a school for my RN-BSN they told me to get the blood test. min $250 out of pocket. I can get a TB skin test at the health dept for $15. They told me to go to employee health. Like they are going to pay for an expensive test like that. I worked in LTC and had it done every year. It is no big deal to get the skin test

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Specializes in Emergency, Telemetry, Transplant.

You would only need to get 2 steps once, assuming you get at TST yearly every year after the original 2 step (at least that is how it is everywhere I've ever worked). I get it placed on, say, a Monday when I work, get it read Wed. or Thursday (any RN/doc can read it...it does not have to be at work--at least for my facility).

Plus (and I realize this is not a universal opinion), I'd rather get the TST as opposed to getting stuck for blood.

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Specializes in PACU.

I have always done the PPD util this most recent hire. They did the IGRA, they told me because the did so many TB tests (large hospital chain) they were able to secure a good contract to decrease their cost and then they didn't have to follow up and chase people down on all shifts to read them. Since my Hep B series was done such a long time ago, they drew a titer for that... all one slick and quick blood draw. I'm all on board for this, new to me, way of doing things.

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As stated in other replies, the quantiferon gold is historically very very expensive. I had a positive PPD and a negative chest X-Ray. I was told to do the anti-tb regimen (about 6 months of liver and kidney toxic drugs) because I had latent TB. I asked my employer about the blood test before I would agree to treatment because I was not convinced I even had latent TB. They denied my request but my PCP agreed. My quantiferon gold was negative. Now I just answer the TB screening questionnaire every year and that's it. No PPD (because I had a reaction) and no chest X-ray because the blood test showed that I don't have even latent tb that needs to be monitored.

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I got a TB blood test because i kept forgetting to go back and get it read in Time. Cost ended up less for me. TB test for admin and reading at CVS was over 50 bucks and i had to get 2 of them. I ordered the TB blood Test online through Order any Lab Titers, Wellness Labs, STD test and more online. – LabReqs.com and cost for TB blood test was $129.00. C

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