The study was of 2204 contacts using QuantiFERON® TB Gold In-Tube and TST.
Presented at the British Thoracic Society’s London meeting in November, this exciting study compared QFT and the TST progression rates to active TB in contact screening.
The data show QFT to have 100% negative predictive value because no one who tested QFT-negative (or QFT-negative/TST-positive) progressed to active TB (n = 835).
The key finding is that QFT is highly predictive of active TB; a sixth of “QFT Positive” contacts, left untreated, progress to active TB within 2 years, a rate which compares favorably with that observed with TST (1 in 50–100 cases).
The flow-chart below shows the progression to active TB by group(click on image for FULL SIZE)
The study abstract was mentioned here and the presentation is available from www.gnowee.net
