Differences in Clinical Manifestations according to the Positivity of Interferon-γ Assay in Patients with Intestinal Tuberculosis

Intestinal tuberculosis (ITB) remains prevalent in Asia. An interferon-gamma assay (QuantiFERON-TB gold test [QFT]) is considered to be an effective supplementary tool for diagnosing ITB. We retrospectively analyzed the clinical features of ITB patients based on the initial results of QFT. A total of 109 patients with ITB were enrolled, and 82 patients (75.2%) showed positive QFT results. In the QFT-positive group, the mean age (44.1 +/- 12.0 years) was significantly higher than that in the QFT-negative group (37.0 +/- 14.8, p=0.0096). Abdominal pain (p=0.006) and diarrhea (p=0.030) were more frequent in the QFT-negative group. Further, C-reactive protein (CRP) levels were significantly higher in the QFT-negative group (6.4 +/- 9.9 mg/dL) than in the QFT-positive group (1.3 +/- 2.3, p<0.001). Multivariate analysis confirmed that younger age (p=0.016), diarrhea (p=0.042), and high levels of CRP (p=0.029) were independent predictors of QFT-negative results in patients with ITB. These results suggest that prior exposure to TB, reflected by QFT positivity, may cause mild inflammation in patients with ITB.