geoffrey modest medical blogs

Given the recent article of the USPSTF LTBI (latent TB infection) recommendations (added on below for your reference) I decided to bring up another study which questions the role of  IGRAs ( interferon- γ  release assays ) --see  tb igra tspot amjrespcare2015  in dropbox, or King TC. Am J Respir Care 2015; 192(3): 367. I initially decided that the prior articles and blogs were pretty concerning about the stability of IGRAs, but this study does add another wrinkle: it was an industry-sponsored study, still had pretty striking conclusions that 1 in 5 people with positive IGRAs would revert to negative, yet then concluded that T-SPOT. TB  (one of the IGRAs) is "an accurate and reliable way to screen healthcare workers". details: --20,095 pairs of  T-SPOT. TB   results from 16,412 health care workers (HCWs) at 19 geographically diverse US hospitals (urban, suburban, rural), looking at serial  T-SPOT. TB   ​ testing, ...

The USPSTF just came out with their recommendations for screening for LTBI (latent TB infection) in populations at increased risk, giving it a "B" Grade (a recommended service, with "high certainty that the net benefit is moderate, or there is moderate certainty that the net benefit is moderate to substantial"  (see  tb  LTBI recs uspstf2016  in  dropbox , or go to  http://www.uspreventiveservicestaskforce.org/Page/Document/UpdateSummaryFinal/latent-tuberculosis-infection-screening  ). details: Background: --the Natl Health and Nutrition Examination Survey in 2011-12  found  a national prevalence of LTBI  of  4.7% of the US population and 20.5%  in t hose foreign-born --5-10% of those with LTBI progress to active TB during their lifetime Results: --Benefits of screening     --no eligible studies were identified showing that targeted screening for LTBI in primary care...

The USPSTF just circulated a draft recommendation for screening for latent TB infection (LTBI) -- see  http://www.uspreventiveservicestaskforce.org/Page/Document/draft-recommendation-statement144/latent-tuberculosis-infection-screening ​ . in brief, they are recommending that adults "who are at increased risk for TB" be screened, grade B recommendation (high certainty that net benefit is moderate). details: --the 2011-12 National Health and Nutrition Examination Survey estimates the prevalence of LTBI in the US at 5% (worldwide, about one-third of the world's population is infected with TB, with 1.5 million deaths in 2014. in the US there were 555 deaths in 2013) --30% of those exposed to Mycobacterium TB develop LTBI; of these, 5-10% progress to active TB disease --those at increased risk for TB: born in or were former residents in countries with increased TB prevalence, or have lived in high-risk congregate settings (eg, homeless shelters, correctional faciliti...

a recent article found the disturbing result that the  Interferon-γ release assays (IGRAs) ​ for tuberculosis seems to have many false positive results (see  tb igra false pos amjrespcare2013 ​ in dropbox, or DOI: 10.1164/rccm.201305-0831OC). this is particularly disturbing since there is a national shortage of PPD testing reagents, leading many institutions to rely heavily or exclusively on IGRAs [70 have adopted QuantiFERON-TBGold (QTF)]. I sent out a blog a couple of years ago questioning the validity of IGRAs at the Cleveland clinic.  The current study is more impressive and with larger numbers of health care workers.  For background reference, MMWR did a full issue on PPD vs IGRAs in 2010 (see  http://www.cdc.gov/mmwr/pdf/rr/rr5905.pdf . ).  There was some concern voiced to me by a TB specialist member of the committee involved in producing this paper at that time, stating that most of the committee members voicing approval for IGRAs (not includi...