CTCA Position – Response to Tubersol Shortage
Tubersol is one of the formulations of purified protein (PPD) solution used for the Tuberculin skin test (TST) as a diagnostic for TB infection and disease. There is a nationwide shortage of
PPD solution for the second time this year. The shortage is projected to last through October, but the reliability of a continuous supply is uncertain.
The alternative to the TST for TB testing is the interferon gamma release assay (IGRA) blood test. This test is available through both public health and commercial laboratories. Per test, the cost of the IGRA as compared to the TST is generally higher for patients and facilities that must comply with mandates for TB testing (e.g. health care facilities, corrections facilities, mental health institutions). At present, Qiagen, the supplier of the Quantiferon, which is one of two commercial IGRAs available, has disclosed that selected laboratories are reporting high indeterminate rates. This is considered a test result failure. The higher indeterminate rate is attributed to a new batch of mitogen (positive control) that is more sensitive to specimen handling and has a lower reactivity than previous mitogen in the QFT assay.
TB controllers and local health officers are providing guidance to use the existing Tubersol supply as effectively as possible. The groups prioritized for TB tests include people who have symptoms of active TB disease or have known contact to a case of active infectious TB disease. There are also a large number of people who are required to have TB testing done as dictated by state mandates or facility licensing requirements. A considerable number of people required to undergo TB testing are low risk for TB infection and disease and could be screened using a TB risk assessment questionnaire instead of a TB test.
The combination of factors which include: 1) the chronic PPD solution shortage, 2) QC problems encountered with the alternate QFT test, and 3) large numbers of people that are required to have TB testing to fulfill state mandates and licensing requirements has stressed the day to day operation of health care facilities, educational institutions, correction facilities, and public health programs across the state.
Community organizations have asked local health officers whether they have the authority in this situation of drug shortage to suspend state mandated TB testing in lower risk populations.
Local health officers and TB controllers would like to receive a response from state authorities or licensing agencies about the feasibility of flexibility during this shortage such as: 1) using a
TB risk assessment questionnaire to fulfill the TB screening requirement for such populations as school volunteers, community college employees, other employees working in K-12 education, 2) prioritizing higher risk health care workers for annual TB testing while using symptom review in lower risk health care workers to fulfill both state mandates and licensing requirements.
As part of the response to this shortage, CTCA recommends that the California Conference of
Local Health Officers review the health officer authority to suspend state mandated TB testing of low risk populations, and to seek flexibility from state authorities and licensing agencies for annual TB testing requirements in this time of drug shortage. www.ctca.org