As a result of a 3- to 10-month nationwide shortage of Aplisol® (Par Pharmaceuticals, Woodcliff Lake, NJ), 1 of the 2 purified-protein derivative tuberculin antigens licensed by the Food and Drug Administration (FDA) for use in performing tuberculin skin tests, the Centers for Disease Control and Prevention (CDC) has issued 3 recommendations for mitigating a reduction in tuberculosis testing capability, which were published in the Morbidity and Mortality Weekly Report.

The manufacturer informed CDC of an interruption in supply of Aplisol 5 mL (50 multidose vials) beginning in June 2019, as well as an interruption in supply of Aplisol 1 mL (10 multidose vials) in November 2019. To mitigate this shortage, CDC advises that clinicians should do the following:

1) Substitute interferon-gamma release assay blood tests for tuberculin skin tests. CDC advises that clinicians be aware of the different criteria for interpreting test results between the 2 types of immunologic methods.

2) Substitute Tubersol® (Sanofi-Pasteur, Lyon, France), the other purified-protein derivative tuberculin antigens licensed by the FDA, in place of Aplisol for skin testing because there is a high concordance between the 2 products.

3) Prioritize allocation of tuberculin skin tests, testing only people who are at high risk for tuberculosis infection.

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While test concordance is high, CDC noted that switching between tuberculin skin tests and blood tests “in serial testing might result in apparent conversions from negative to positive or reversions from positive to negative that might be attributable to inherent interproduct or intermethod discordance rather than change in Mycobacterium tuberculosis infection status.” As such, “clinicians should assess test results based on the person’s likelihood of infection and risk for progression to [tuberculosis] disease, if infected.”

Reference

Centers for Disease Control and Prevention (CDC). Nationwide shortage of tuberculin skin test antigens: CDC recommendations for patient care and public health practice. MMWR Morb Mortal Wkly Rep. 2019;68(24):552-553.

This article originally appeared on Infectious Disease Advisor