Ask the expert: Positive TB test with new hires

By: June 15th, 2012 Email This Post Print This Post

Q: We are a low-risk setting for TB. What is the follow-up when a new worker has a positive skin test for TB?

A: According to the CDC’s Guidelines for Preventing the Transmission of Mycobacterium tuberculosis in Healthcare Settings, 2005, “New hires with a baseline positive or newly positive test result for M. tuberculosis infection should receive one chest x-ray result to exclude TB disease (or an interpretable copy within a reasonable time frame, such as 6 months).”

On the matter of repeat chest x-rays, unless symptoms or signs of TB disease develop or unless recommended by a clinician, additional x-rays are not necessary for new hires in a low-risk setting,s according to the Guidelines.


By Kay Williams, BSN, MPH CIC on June 15th, 2012 at 11:19 am

1. What value do you place on Quantiferon Gold TB test vs. chest xray when questionnaire is negative for any pulmonary symptoms? Some health systems are using Quantiferon Gold TB test instead of shcest xray which only would identify active pulmonary process.
2. What about the rapid TB test for screening newhire or annually?

Our company went to the QFT-G test because it is so much more convenient for the New Hire and there is less subjectivity. However, when we get a positive, we still send them for CXR to r/o active disease, even though their TB Questionnaire is negative. We too are a low risk facility, but please clarify did OSHA supercede the CDC TB guidelines and impose annual testing for all??? We haven’t been doing that, just retest upon exposure. Considering annual testing for Urgent Care and hospitalists because of their greater likelihood of running into a positive patient unknowingly. Lauren

We are a low risk facility and do annual testing on all pt care nursing staff, physicians but it is not required for non clinical staff. If we had a positive upon hire we would send that person to have the quantiferon testing rather than a cxr in most cases. we used to just do the cxr but have recently changed our process. I look forward to repsonse to both Kay and Lauren’s questions.

By David LaHoda on June 15th, 2012 at 12:49 pm

The OSHA letter of interpretation “06/23/2009 – Whether annual TB skin testing is required for low risk personnel,” explains that “An employer’s adherence with the recommendations of the most recent CDC guidelines would be considered to meet the provisions of the general duty clause,” on which previous OSHA references to annual TSTs was based.

Whew, that’s a relief; thanks, David. From my reading, QFT-G is more of an equivalent for TST, rather than a higher level of test. But I sure like your idea…then if you get a positive blood test you would send for cxr, right?

By David LaHoda on June 15th, 2012 at 1:03 pm

“QFT-G may be used in all circumstances in which the TST is currently used, including contact investigations, evaluation of recent immigrants, and sequential-testing surveillance programs for infection control (e.g., those for health-care workers),” according to Guidelines for Using the QuantiFERON®-TB Gold Test for Detecting Mycobacterium tuberculosis Infection, United States.

By Bruce Cunha on June 19th, 2012 at 10:37 am

The IGRA tests (GFT-G and T-Spot) really do not give absolute indication of active TB. While a chest x-ray cannot totally rule out active TB, without any other symptoms, a negative CXR is still the best next step.

We use IRGA for all TB testing and have worked through many of the indeterminants and false positive issue.

For those considering using it. Pay close attention to collection and processing. There are some very specific processes needed to assure a vaid test.

We run thousands of these tests and just got done with a 5 month process of working with Celestis to assure the process was correct. We did this because we saw a higher than normal positive rate and learned that 1. there was a bad tube lot. 2. some of the pre analytical processes were not consistant across our system.

By Kimberly McHatton on June 19th, 2012 at 1:30 pm

What about the new hires that report a history of a +PPD skin test without any documentaion. Often employees will say they had a “terrible” reaction and was told to never have another TST. So besides sending them for a CXR to rule out active TB what is required? Should these employees be evaluated for LTBI especially if they never was assessed or treated before?

I’d say yes, definitely! Ideally send them to the lab for QuantiFERON TB-Gold, which, I have found in many cases of “I’m always positive”…to be negative, which is reassuring for all. If the blood test is positive it is a good indicator for latent TB. At that point we used to send our new hires for a 2v CXR to take to the Public Health department to have the cxr and positive lab evaluated. Now lately, Public Health has been undermined by staffing cuts and only want us to send people who have already decided to take meds for the latent TB. This is MUCH better than relying on their word. Lauren

By sbarckley on June 27th, 2012 at 2:45 pm

Does OSHA require medical staff that work in the Clinical areas to do TB-skin test

We recently had the Tech Rep come in and set up the Quantiferon TB Gold test in our lab. I had several employees drawn the day before the set up so I would have some patients to run. I ran them the first day of training-all positive. Redrew everyone-positive again. Ordered new lot of tubes-redrew-all negative with a 4 point and 8 point curve-has anyone else besides Bruce Cunha and myself had this problem?

What kind of follow-up do you do if you believe you have a false positive based on the risk assessment? Thank you

By Felecia Wyatt on June 26th, 2019 at 3:01 pm

If a company hire an employee who has had a positive tb skin test in their past but has no documentation. Can employer require an employee to take a tb skin test?


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