TB Skin Test Antigens in Short Supply Again, CDC Says

September 05, 2013

For the second time this year, clinicians battling bacterial tuberculosis (TB) will have to cope with shortages of 2 tuberculin skin test (TST) antigens, the Centers for Disease Control and Prevention (CDC) announced yesterday in a Health Alert Network advisory.

The scarce TST antigens are Tubersol (Sanofi Pasteur) and Aplisol (JHP Pharmaceuticals), both purified-protein derivative tuberculin products approved by the US Food and Drug Administration (FDA).

The agency said that the 50-dose vials of Tubersol are unavailable, and supplies of the 10-dose vials are limited. The CDC does not expect supplies to be replenished until at least the middle of October.

The scarcity of Tubersol has caused healthcare providers to switch to Aplisol, which has created regional shortages of the latter product. JHP Pharmaceuticals is giving established Aplisol customers precedence over new ones and restricting the quantity of the TST antigen they can buy.

The CDC issued an alert about these very same circumstances in April. At that time, the agency said supplies of Tubersol would not be restored until at least the end of May. Yesterday's alert said the shortage was resolved in early June.

3 Shortage Work-Arounds

As it did in its April alert, the CDC is recommending steps that public health officials, clinicians, and occupational health and infection control personnel can take to work around the shortages of TST antigens.

  • Substitute interferon-gamma release assay tests for TSTs. However, these tests come with drawbacks: Unlike TSTs, they can yield indeterminate or borderline results, and they also can cost more.

  • Substitute Aplisol, if available, for Tubersol. "The two products give similar results for most patients," said the CDC.

  • Prioritize the use of TSTs. First priority might go, for example, to TB contact investigations.

Updates about the shortage of TST antigens are available on the Web site of the FDA's Center for Biologics Evaluation and Research.


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