Use of the QuantiFERON®-TB Gold Assay in Pregnant Patients

Background. The QuantiFERON -TB Gold assay is a new test for latent tuberculosis infection. It is thought to be more reliable and have fewer false positives than the tuberculin skin test (TST). Both tests are dependent on a normal immune system for diagnostic accuracy. However, no comparisons of the two tests have assessed the accuracy in pregnant women. This investigation assessed the consistency of results between the two tests in both pregnant and nonpregnant women. Methods. The study included 152 women presenting for care at the Sedgwick County Health Department. They were divided into two groups of pregnant and non-pregnant women. Both groups were assessed with the Quantiferon assay and the TST. Subjects were adults between the ages of 18 and 45. All had a pregnancy test and a negative HIV test. None had existing morbidities that would influence the test results. Results. Concordant results between the tests were shown in 131 subjects (86.2%). Of the pregnant women, 91.2% had concordant results. Of the non-pregnant women, 76% had concordant results. Significantly more discordant results occurred in non-pregnant women (p<.022). Conclusion. Current guidelines favor using either test in healthy individuals. Although more discordant results occurred in the non-pregnant women, both tests were effective in pregnant women. Thus, TST and Quantiferon are accurate to use in pregnant women. The decision to use either test in pregnant women should be based mainly on the compliance of the patient to return to have the TST read. KJM 2010; 3(2):24-30.