Effect of recent PPD on Quantiferon

[socky1938]

Hello,
My question is regarding the Quantiferon-Gold test. My son age 13, tested positive on the PPD Skin test for TB (14mm) on Dec 4, 2009 (results read at 8 am). He has had previous skin tests done on two ocassions (2000, and then in 2007). He has also received BCG, was born in India, moved to USA when he was 3 years of age, and has never travelled outside of USA ever since. His chest X-rays in 2000 and 2007 were clear, but his chest x-rays (done for a different reason) in March 2009, and then Nov 2009 showed a lower hazy infiltrate in the left lobe. He was wheezing the past, but is no longer wheezing. Asthma and allergy clinic tested him for allergies (which he has quite a few).

He had his PPD done on evening (5 pm) of Dec 1, 2009, which was positive (14 mm). Today is Dec 7, 2009. I need to get his Quantiferon Gold test. My question is that would the PPD of Dec 1, 2009 affect the results of his Quantiferon tests, if he were to go for a blood draw today?

[David Tinkelman, M.D.]

The report cited at the end of my reply suggests a possible booster effect of PPD.  The PPD reaction of 14 mm is strongly positive and unlikely to be secondary to BCG, administered in the distant past.  Both tests, PPD and Quantiferon must be considered as suggestive but not confirmative of active tuberculous infection.  While the presentation of infection with TB in a lower lobe is much less likely than presentation in the upper lobes, it can occur.  You may want to ask his doctors if CT scanning of the “hazy infiltrate” might shed more light on the possibility of its being a manifestation of active infection with TB.  Sputum induction or bronchial washings via fiberoptic bronchoscopy could provide more direct evidence, either for or against the diagnosis.

I would also suggest that you request that your son’s doctor call the Physician’s Consultation Line at National Jewish Health in Denver, a center of expertise in the diagnosis and treatment of TB.  To arrange for a National Jewish Health Physician Consultation, your son’s physician can visit the following website or call1-800-652-9555  
https://www.nationaljewish.org/about/contact/phys-consult-form.aspx

Good luck






TitleBooster phenomenon of QuantiFERON-TB Gold after prior intradermal PPD injection.[see comment].
Authors Full NameIgari, H. Watanabe, A. Sato, T.
InstitutionDivision of Control and Treatment of Infectious Diseases, Chiba University Hospital, Chiba, Japan. ***@****-u.jp
Comment in: Int J Tuberc Lung Dis. 2007 Dec;11(12):1381; author reply 1381; PMID: 18034964
SourceInternational Journal of Tuberculosis & Lung Disease. 11(7):788-91, 2007 Jul.
AbstractSETTING: University medical school in Japan. OBJECTIVE: To clarify the influence of prior intradermal purified protein derivative (PPD) injection on QuantiFERON-TB Gold (QFT-G). DESIGN: Ninety-seven sixth-year university medical students aged 20-29 years concurrently underwent QFT-G and tuberculin skin test (TST). The first negative QFT-G and the first TST <15 mm were followed by a second QFT-G one month later. RESULTS: Five of the 97 (5%) subjects tested positive for the first QFT-G. Thirty-three underwent a second QFT-G, five of whom (15%) turned positive, demonstrating the booster phenomenon of QFT-G. CONCLUSIONS: Prior intradermal PPD injection may boost QFT-G. Further studies of the diagnostic significance and immunological mechanisms of this phenomenon are needed. For clinical application, especially during contact screening, QFT-G should be evaluated while keeping in mind the possible influence of prior PPD intradermal injection.

[harold123]

Perhaps if you contacted the manufacturer, they would be able to advise you of any issues with regards to time of placement and possible boosting effects, if any, of the skin test.

The manufacturer is here http://www.cellestis.com/