PPD Shortage Prompts CDC to Issue New Recommendations for TB Testing

The Centers for Disease Control and Prevention (CDC) announced an expected 3 to 10 month shortage of Aplisol (tuberculin purified protein derivative [PPD], diluted), used as an aid in the diagnosis of tuberculosis (TB).

Par Pharmaceuticals, the manufacturer of Aplisol, alerted the CDC that a supply interruption of Aplisol 5mL (50 tests) will begin this month, while the 1mL product (10 tests) is expected to be in shortage by November 2019, and possibly earlier if there is an increase in demand.

Because of the expected shortage, the CDC is recommending the following:

• Substitute interferon-gamma release assay (IGRA) blood tests for tuberculin skin tests (TSTs); both types are used to detect Mycobacterium tuberculosis infection, however the criteria for test interpretation of IGRA blood tests are different from those of TSTs.
• As similar results have been observed with Tubersol (tuberculin PDD, Mantoux; Sanofi Pasteur), another FDA-approved PPD tuberculin antigen, it may be used as a substitute for skin testing.
• Prioritize allocations of TSTs, in consultation with state and local public health authorities. The CDC recommends only testing those who are at risk of TB (ie, recent contacts exposed to persons with TB disease; born in or frequently travel to countries where TB is prevalent; individuals living in large group settings [ie, homeless shelters, correctional facilities], immunocompromised individuals, children [especially those <5 years old] if they are in one of the risk groups).
• In settings where the likelihood of TB exposure is low, deferment of routine serial testing should be considered; annual testing of healthcare personnel is not recommended unless there is a known exposure or ongoing transmission.

According to a statement from the CDC Health Alert Network, clinicians should be aware that “switching between PPD skin test products or between TSTs and blood tests in serial testing may cause apparent conversions of results from negative to positive or reversions from positive to negative. This may be due to inherent inter-product or inter-method discordance, rather than change in M. tuberculosis infection status.”

The status of the Aplisol shortage can be monitored by visiting the FDA’s product shortages page.

For more information visit parsterileproducts.com.

This article originally appeared on MPR