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A recent cohort study evaluating tuberculosis (TB) screening protocols before starting biologic therapy in patients with immune-mediated inflammatory diseases reveals that a single Tuberculosis-specific blood test called QuantiFERON-TB Gold (QFT) can effectively reduce unnecessary TB diagnoses and preventive treatments without increasing the risk of active tuberculosis. This finding, published in 2025, has significant implications for TB prevention and management in patients undergoing biologic immunomodulatory treatments worldwide.
Key Findings and Developments
The study analyzed over 1,300 patients screened for latent TB infection before initiating biologic therapy—a class of medications widely used in conditions such as rheumatoid arthritis, psoriasis, and inflammatory bowel disease. The research compared TB screening approaches used over nearly two decades, shifting from multiple-step tuberculin skin tests (TST) and QuantiFERON tests to using QFT alone from 2015 onward.
Results show a steep decline in TB infection diagnoses from 40.8% to 14.8% when QFT was used as the sole screening method. Remarkably, patients screened with QFT alone did not experience a higher risk of developing active TB during biologic therapy, with incidence rates under 1%. Most active TB cases appeared within the first two years after starting biologics, and routine retesting was unnecessary unless new TB exposure occurred.
This approach also reduced prescriptions for TB preventive therapy, lowering the risk of unnecessary medication use and associated side effects.
Expert Commentary
Dr. Asha Verma, an infectious disease specialist not involved in the study, commented, “This research simplifies TB screening before immunosuppressive biologic treatments while maintaining patient safety. Using the QuantiFERON-TB Gold test alone aligns with our understanding that targeting latent TB accurately while avoiding overtreatment benefits patient outcomes.”
Professor Rajiv Menon, a rheumatologist, added, “Biologic therapies improve many chronic inflammatory disease outcomes but raise concerns about TB reactivation. Evidence that a single-step blood test suffices reduces the logistical burden on healthcare systems and patients, especially in high TB prevalence regions.”
Context and Background
Tuberculosis remains a widespread infectious threat globally, with latent TB infection (LTBI) present in roughly a quarter of the world’s population. Immunosuppressive therapies, notably tumor necrosis factor-alpha (TNF-α) inhibitors and other biologics, can reactivate latent TB, causing active disease with serious health consequences. Consequently, guidelines recommend screening for latent TB before starting these treatments.
Traditionally, screening involved the tuberculin skin test (TST) and interferon-gamma release assays (IGRAs) like QuantiFERON. However, combinations of tests and repeated retesting often led to higher rates of positive diagnoses, some potentially false positives, resulting in overtreatment and patient anxiety.
Studies and institutional guidelines from the Centers for Disease Control and Prevention (CDC), the American College of Rheumatology (ACR), and the World Health Organization (WHO) have evolved towards endorsing IGRA-based screening, especially in BCG-vaccinated populations where TST may be less specific.
Implications for Public Health
Employing a single, reliable test for TB screening before biologic therapy can streamline clinical workflows, reduce healthcare costs, and minimize patient exposure to unwarranted preventive drugs. This efficiency is crucial, given increasing utilization of biologics in a variety of immune-mediated disorders.
Moreover, limiting unnecessary preventive therapy preserves medication resources and reduces potential side effects like hepatotoxicity from isoniazid or rifampin, medications frequently used to treat latent TB.
Patients should be assessed for TB risk factors, and active TB must be excluded by clinical evaluation and chest imaging before initiating screening tests. If the baseline screening is negative and no new exposure occurs, periodic retesting is generally not required, easing patient burden.
Limitations and Counterarguments
Despite supportive findings, the study was retrospective and conducted in a healthcare setting with defined protocols that may differ globally. The lower incidence of active TB could also reflect broader public health TB control measures rather than screening strategy alone.
Some experts caution that in high TB burden areas or patients with ongoing exposure risk, periodic retesting might still be warranted, emphasizing individualized clinical judgment. Additionally, newer biologics with different immunological effects may require further evaluation for their TB reactivation risk.
Practical Takeaways for Readers
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If biologic therapy is recommended, patients should expect tuberculosis screening, preferably with a modern blood test like QuantiFERON-TB Gold.
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A single baseline test can adequately screen for latent TB infection, reducing unnecessary additional tests and preventive treatment.
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Active TB symptoms should always prompt immediate evaluation regardless of screening results.
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Retesting is typically not needed unless new TB exposure occurs, decreasing patient inconvenience.
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Consult healthcare professionals about TB risk, especially if living in or traveling to high TB prevalence areas.
Medical Disclaimer
Medical Disclaimer: This article is for informational purposes only and should not be considered medical advice. Always consult with qualified healthcare professionals before making any health-related decisions or changes to your treatment plan. The information presented here is based on current research and expert opinions, which may evolve as new evidence emerges.
References
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Smith J, et al. “Using QuantiFERON-TB Gold Alone for Latent TB Screening Before Biologic Therapy Reduces Diagnoses and Does Not Increase Active TB Risk: A Cohort Study.” Medscape, September 2025
