Click below to hear recorded Q&A audio for each question from our live webcast audience.
If there was a positive TB skin test, and you wanted to perform QuantiFERON®-TB Gold/Plus to confirm, is there a waiting period between the tests?
Should routine tuberculin skin testing be done on high-risk populations? For example, drug treatment centers, methadone clinics? Or is a screening sufficient with follow-up if symptoms or changes are identified?
Do steroids make IGRA inaccurate?
How do you recommend we deal with an indeterminate QuantiFERON result?
What should we do if someone has a borderline T-SPOT®.TB test, and one week later, has an invalid T-SPOT.TB test? How soon should we retest?
Is it OK to repeat QuantiFERON-TB Gold test after the patient finished prophylactic treatment for latent TB infection?
When will the standards for testing change from TST to IGRA?
The first question, Dr. Ali, I’ll ask in two parts. The first part is, if someone got BCG, and got PPD testing, is it always positive, regardless of the size of redness? Or is it positive for TB only if less than one centimeter erythema?
Thank you. And the second part of that question, how do you interpret erythema size with the history of BCG?
Our next question is, what is the incidence of false positives with IGRA?
The next question is, if someone has had a TST from an outside provider, and got a questionable result, how long do you suggest waiting to do an IGRA?
Our next question is, can you please talk more about PPD boosting?
What do you do if the QuantiFERON comes back indeterminate?
Please indicate the limitation on why the QFT is limited with HIV/AIDS.
What is the impact of live vaccination and IGRA?
What does it mean when a T-SPOT.TB test is positive, and a TST is negative, or vice versa?
Our next question is of a follow-up, a vaccination question. If the patient receives live vaccination and we test the patient with QuantiFERON, do we have to wait for four to six weeks before QuantiFERON testing, will the result be affected?
Do you see the elimination of the TST, I guess being eventual, because, both because the IGRA is more specific, and because of the national shortage of Aplisol®, thus causing a reduction in tuberculin?
Our next question is for a patient that was treated for uncomplicated TB, about a six-month treatment, maybe two years ago, would the IGRA remain positive? And if so, for how long?
The next question is, in the case of a known LTBI that occurred years ago, should we still encourage treatment?
The next question is, what is the likelihood of an individual going from no TB directly to active TB versus going from no TB to LTBI, to active TB?
If an IGRA tests positive, what are the next steps?
T-SPOT is a registered trademark of Oxford Immunotec Ltd.
QuantiFERON and QFT are registered trademarks of the QIAGEN Group.
Aplisol is a registered trademark of Par Pharmaceutical, Inc.
About our Speaker
Juzar Ali, MD, FRCP(C), FCCP
Dr. Ali is a Professor of Medicine at Louisiana State University Health Sciences Center, New Orleans and Director of the LSU-Wetmore Mycobacterial program. He is also attached to the regional office of Public Health through the Wetmore TB clinic. He is an academic clinician with special clinical and research interests in mycobacterial diseases and bronchiectasis within the section of Pulmonary Critical care at LSUHSC New Orleans.
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