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

Abstract

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.

Effect of pregnancy and HIV infection on detection of latent TB infection by Tuberculin Skin Test and QuantiFERON-TB Gold In-Tube assay among women living in a high TB and HIV burden setting

“…In addition, this study demonstrated that the concordance between TST and QFTGIT increased in the presence of pregnancy or HIV infection, with the highest agreement appearing in women with both conditions. In agreement with this finding, previous studies also showed an increased concordance of TST and QFTGIT in HIV-positive compared to HIV-negative individuals (Lin et al, 2016) as well as in pregnant compared to non-pregnant women (Chehab et al, 2010). The increased agreement due to the underlying HIV infection and pregnancy could be related to the selection of participants with better immune competency and deteriorated sensitivity of the tests, resulting in a higher concordance between TST and QFTGIT results.…”

“…This could be due to the waning effect of childhood BCG vaccination over time in women of reproductive age. However, prior BCG vaccination was associated with positivity of TST but not QFTGIT (Chehab et al, 2010;Worjoloh et al, 2011) because the PPD used in TST is also present in the BCG vaccine whereas antigens used in QFTGIT are specific to M. tuberculosis (Huebner et al, 1993;Wang et al, 2002). Furthermore, although this study and others (LaCourse et al, 2017;Latorre et al, 2010) showed that HIV-positive women with elevated CD4 + T-cell count had a relatively higher detection rate of LTBI by these tests, there was no significant association between the positive TST and QFTGIT results and the CD4 + T-cell count.…”

Interferon Gamma Release Assay Compared With the Tuberculin Skin Test for Latent Tuberculosis Detection in Pregnancy

“…(31–33) In the only other study we know of that compared tuberculin skin test and interferon gamma release assay results in healthy pregnant women, Chehab et al found 91% agreement between tuberculin skin test and interferon gamma release assay among pregnant women in Kansas. (17) However, the prevalence of tuberculin skin test or interferon gamma release assay positivity was very low in this study population (less than 10% of positive tuberculin skin test and less than 5% of positive interferon gamma release assay), which may explain the higher agreement between the two tests. (34)…”

“…Moreover, few studies have evaluated the use of interferon gamma release assays in normal pregnancy. (17)…”

Effect of Pregnancy on Interferon Gamma Release Assay and Tuberculin Skin Test Detection of Latent TB Infection Among HIV-Infected Women in a High Burden Setting

“…This pattern of discordance (IGRA+/TST−) differs from the predominant discordance pattern (TST+/IGRA−) observed in studies of HIV-negative pregnant women in low TB incidence settings. [12–14] In settings with lower risk of TB transmission, a positive TST may reflect false positivity due to BCG vaccination rather than Mtb infection, leading to a higher proportion of TST+/IGRA−. [15] Additionally, most studies have been cross-sectional, and do not capture potential dynamic effects of peripartum stage on LTBI diagnostics.…”