QuantiFERON and HCWs

Back in January the academics at McGill advised that

Studies have suggested that the lower prevalence of LTBI using IGRAs will result in fewer numbers of HCWs who require preventive therapy. However, the higher rate of subsequent conversions found by IGRA in these studies suggests that, while fewer individuals may be identified as LTBI at baseline, more individuals could be diagnosed with conversions by IGRA leading to more HCWs requiring preventive therapy upon repeated screening.

Faced with this apparent dilemma they advise

Until further evidence is available, TBIC programmes that include IGRA testing must use caution

This hasn't deterred those in Korea

Our data shows the high prevalence of LTBI in the laboratory personnel, and emphasizes the importance of LTBI screening for the health care workers. QFT-G seems to be superior to TST for the LTBI screening.

or Spain

1.- Agreement between TST and QFT was low in vaccinated and non-vaccinated people.
2.- QFT was better than TST for recent tuberculosis infection diagnosis in health care workers because of its high specificity and no interference of booster
3.- QFT was a better indicator for treatment of tuberculosis infection.

Further studies addressing IFN-y sero-convertion and –reversion in health care workers for the follow-up of health care personnel are needed.

On the last point it appears that the lack of evidence on conversions and reversions was not sufficient to halt the use of QuantiFERON.