Medication Monitor

Generic Name (Trade Name—Company)
June 25, 2019

Tuberculin antigen

(Aplisol—Par Pharmaceuticals)
Nationwide shortage of tuberculin skin test antigens

On June 21, CDC announced a 3- to 10-month nationwide shortage of Aplisol (Par Pharmaceuticals), one of two purified-protein derivative (PPD) tuberculin skin test antigens licensed by FDA for use in performing tuberculin skin tests. The manufacturer notified CDC that it anticipates an interruption of supply of Aplisol 5 mL (50 multidose vials) beginning in June 2019, followed by an interruption of the supply of Aplisol 1 mL (10 multidose vials) in November 2019. The expected shortage of Aplisol 1 mL could occur before November 2019 if demand increases before then.

Two types of immunological methods (tuberculin skin tests [TSTs] and interferon-gamma release assay [IGRA] blood tests) are used for detecting Mycobacterium tuberculosis infection. TSTs and IGRAs are used for the diagnosis of latent TB infection and can aid in the diagnosis of TB disease, but additional evaluation and testing are necessary to distinguish between latent TB infection and TB disease to determine the appropriate treatment. When findings such as chest radiography and mycobacterial cultures are sufficient for confirming or excluding a TB diagnosis, the results from a TST or an IGRA blood test might not be needed. However, most TB cases in the United States are diagnosed through a combination of findings, including results from one of these tests. When TB disease is strongly suspected, specific treatment should be initiated, regardless of results from TST or an IGRA blood test.

CDC recommends the following three general approaches to mitigate a reduction in TB testing capability resulting from the expected shortage of Aplisol:

• Substitute IGRA blood tests for TSTs. Clinicians who use the IGRA blood tests should be aware that the criteria for test interpretation are different from the criteria for interpreting TSTs.

• Substitute Tubersol (the other PPD tuberculin antigen approved by FDA), for Aplisol for skin testing. In studies, the two skin test products give similar results for most patients.

• Prioritize allocation of TSTs, in consultation with state and local public health authorities. Prioritization might require deferring testing for some persons. CDC recommends testing only for persons who are at risk for TB. Groups at high risk for TB infection include 1) persons who are recent contacts exposed to persons with TB disease; 2) those born in or who frequently travel to countries where TB disease is common; 3) those who currently or previously lived in large group settings (such as homeless shelters or correctional facilities); 4) persons with compromised immune systems, including those with health conditions or taking medications that might alter immunity; and 5) children, especially those older than 5 years, if they are in one of the risk groups noted above.