How useful is chest x-ray in addition to routine QuantiFERON® in the detection of latent tuberculosis prior to biologics?

Abstract

Screening for latent tuberculosis (TB) infection is recommended prior to commencing some biologics with QuantiFERON®/interferon gamma-releasing assay (IGRA) and chest x-ray (CXR) recommended on the BAD biologics checklist. QuantiFERON® is highly sensitive while CXR is poorly sensitive and poorly specific. In our cohort of 995 patients, 2.3% had a positive IGRA and 8.3% had any abnormality on CXR with just 0.8% suggestive of TB. Patients were just as likely to have an abnormal CXR if they had a positive or negative IGRA (p=0.927). We suggest that routine screening with IGRA alone is sufficient in the dermatology population particularly in the setting of a low TB incidence country such as the United Kingdom.