Clinical Edge

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Repeat LTBI Testing Best in Patients Taking Biologics With New Risk Factors

Key clinical point: Just 1.2% of patients taking biologics with negative tuberculosis test results converted to positive results in annual tuberculosis screenings.

Major finding: In 61 patients who converted from a negative to a positive QuantiFERON test result, 28 patients with latent tuberculosis (46%) and 1 patient with an active case of tuberculosis (2%) were diagnosed and treated.

Study details: An analysis of 5,212 patients taking biologics who received latent tuberculosis testing between August 2007 and March 2019.

Disclosures: Dr. Khanna reported no relevant financial disclosures. A few of her coauthors reported financial relationships with pharmaceutical companies.


Khanna U et al. Arthritis Rheumatol. 2019;71(suppl 10), Abstract 1802.


Guidelines for repeat latent tuberculosis infection testing while on biologics have not been clearly established. This study demonstrates that repeat testing for latent tuberculosis in patients taking biologics showed a low rate of conversion (1.17%). A high proportion of patients who did convert had risk factors for tuberculosis exposure. These results suggest that screening by exposure to risk factors may be more cost-effective and clinically feasible than regular screening. The study was only single center, so may not be representative of other treatment sites. Nonetheless, the determination of ordering tuberculosis testing should be individualized by risk exposure.—Paul S. Yamauchi, MD, PhD; Clinical Assistant Professor of Dermatology David Geffen School of Medicine at UCLA; Harbor-UCLA Medical Center Division of Dermatology; Adjunct Associate Professor John Wayne Cancer Institute.