ALK-Abelló withdraws lot of pecan nut allergen extract

Cosby A. Stone Jr., MD, MPH

Skin test extract withdrawals are significant because they require everyone to stop and think about the tests that we are performing on a regular basis, especially tests that we might have performed recently with the withdrawn extract.

Clinicians will ask themselves a lot of questions. Has my practice been affected? Have my patients gotten the right test results? Are we delivering quality test results that can be relied upon to tell us what we need to know, which is whether a patient is likely to be allergic or not? For that reason, withdrawals and recalls are very disruptive. Some patients will need to be tested again.

For manufacturers, recalls of a skin test extract are significant as well. When selling an allergy skin test extract to doctors (and by extension their patients), an extract manufacturer's most valuable currency is a sterling reputation and a commitment to quality. If quality control ever slips, there is a potential for injury due to inaccurate information being provided to your customers. Doctors and patients will notice if there is a mismatch between a skin test performed with a faulty extract and a patient’s real allergy. It will come out.

The main danger from false-negative skin tests is when we use those test results to decide on a future challenge with something that might cause anaphylaxis. A challenge is when an allergy doctor uses your negative skin test as a decision point to give you permission to eat a food that you reacted to previously, either in the office or at home. When skin tests are falsely negative, you would react to that challenge, because the test did not correctly identify your allergy.

Most food allergy skin tests do have a backup, which is blood tests for allergy antibodies against the same food. If the history is consistent with anaphylaxis, but the skin test result is unexpectedly negative, most clinicians will automatically perform blood testing. Then, if we identify a discrepancy where a patient’s history includes anaphylaxis but their skin test shows no allergy and their blood test shows “allergy” without a great explanation, we would talk it through with the patient. One option is to consider testing that patient with a different skin test extract before doing a challenge.

Doctors who perform allergy skin testing will need to check the pecan extracts that they use for the lot that has been withdrawn and replace the withdrawn extract with a different one. They also will need to consider whether there might be patients in their practice who need to be retested. It would be a good idea to proactively contact them, if possible.

Beyond that, it may be time for advocacy. The main thing to note from such stories is that extract manufacturers and the FDA are actively monitoring the quality and safety of extracts that are being used for allergy testing in the United States. This is a very good thing. We are all glad that they do it. However, I think as a community of clinicians, allergy patients, manufacturers and government officials, we are all striving for the same goal. We all want quality skin test results that are safe and reliable.

Therefore, we should be using any extract recall or withdrawal as an opportunity to think about what went wrong and how we can improve. Any time we use a test, patients are counting on us to provide them with the best information possible.