Abstract

Factors That Contribute to Indeterminate Results From the QuantiFERON-TB Gold In-Tube Test in Patients With Inflammatory Bowel Disease

Kaur M1, Singapura P2, Kalakota N2, Cruz G3, Shukla R3, Ahsan S3, Tansel A3, Thrift AP4, El-Serag HB2. Clin Gastroenterol Hepatol. 2017 Nov 23. pii: S1542-3565(17)31411-8. doi: 10.1016/j.cgh.2017.11.038. [Epub ahead of print]
 
     
Author information

1 Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas. Electronic address: mkaur@bcm.edu.

2 Department of Internal Medicine, Baylor College of Medicine, Houston, Texas.

3 Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas.

4 Section of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas; Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas.

Abstract

BACKGROUND & AIMS: The QuantiFERON-Tuberculosis Gold In-Tube (QTF-GIT) (Cellestis Limited, Carnegie, Australia) test is widely used to screen for latent Mycobacterium tuberculosis infection in patients with inflammatory bowel diseases (IBD) before treatment with a tumor necrosis factor antagonist. The test frequently produces indeterminate results, prompting additional testing. We evaluated factors associated with indeterminate results from the QTF-GIT test among patients with IBD.

METHODS: We conducted a case-control study among eligible adults with QTF-GIT test results and a concomitant diagnosis of IBD receiving care at a tertiary referral center from 2011 through 2013. We compared patients with IBD with indeterminate and determinate (positive or negative) results from the QTF-GIT test. We collected data on patient demographics, clinical features, laboratory parameters, and medication use from medical charts. We calculated odds ratios (OR) and 95% CIs using multivariate logistic regression models.

RESULTS: A total of 400 patients with IBD (265 Crohn's disease and 135 ulcerative colitis) were included in the final analyses. Indeterminate results were noted in 11.5% of patients. At the time of testing, a higher proportion of patients with indeterminate results from the QTF-GIT test were on systemic corticosteroid therapy (60.9% vs 30.5% of patients with conclusive test results; P < .001), had levels of C-reactive protein above 0.8 mg (62.2% vs 39.9% of patients with clear test results; P = .005), had an erythrocyte sedimentation rate above 15 mm/h (55.6% vs 35.8% of patients with clear test results; P = .01), had serum levels of albumin below 3.5 g/dL (33.3% vs 6.3% of patients with clear test results; P < .001), and had low levels of hemoglobin (52.2% vs 28.3% of patients with clear test results; P = .001). In multivariable analysis, corticosteroid use (adjusted OR, 2.92; 95% CI, 1.44-5.88; P = .003) and serum levels of albumin below 3.5 g/dL (adjusted OR, 3.62; 95% CI, 1.36-9.60; P = .009) were independently associated with increased risk of indeterminate QTF-GIT test results. We did not identify a dose-related effect with corticosteroid therapy and the odds of indeterminate QTF-GIT test results.

CONCLUSIONS: In a case-control study of patients with IBD, we associated systemic corticosteroid therapy and low levels of albumin with an increased likelihood of having indeterminate QTF-GIT test result.

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