QuantiFERON testing in British army recruits

Abstract

Our hospital has links with an Army base and investigates recruits for Tuberculosis (TB). Many come from high prevalence areas. Recruits are screened with a Mantoux test. Those with a Mantoux reaction ≥15mm and no previous BCG vaccination are referred for QuantiFERON Gold testing. If positive they are treated for latent TB.

We reviewed referrals over a 2 year period (April 2008 - April 2010) to assess compliance with Army policy and investigate whether referral based on Mantoux reaction alone is warranted.

Demographic data were gathered from Army records. The relationship between a positive QuantiFERON test and a Mantoux reaction of ≥15mm was assessed using a Chi-squared test.

153 cases were identified, 28 were excluded due to insufficient data, leaving a sample of 125. All cases were male. Median age was 21.5 years (range 17-33). For analysis recruits were divided into 4 areas (see table 1).

89 recruits (79%) had a positive QuantiFERON test. There was no significant relationship between QuantiFERON positivity and Mantoux size ≥ 15mm (p=0.0923).

Large numbers of recruits are referred based on their Mantoux results, including many with reactions of 6-14 mm. As there was no significant relationship between the rate of QuantiFERON positivity and Mantoux reaction size ≥ 15mm, referral decisions should not be made on this basis alone.

Further research is warranted to assess the current referral guidelines.