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Stability of unrefrigerated allergy extract


We had prolonged power outage due to Hurricane Sandy. We got all of our stock extracts and patient vials in to refrigeration after 48 hours in refrigerators that were without power. What is their reliability?


Thank you for your inquiry.

Unfortunately, I cannot give you a definitive answer. Although we have never had a question directly related to the loss of refrigeration, the answer to your question would be very similar to questions previously posed to our website regarding the mailing of allergy extract, and what effect being without refrigeration during the mailing would have on the stability of the extract.

In researching this question, it became evident that we have no, as noted, definitive answer.

However, we have attempted an answer to this question which, to my knowledge, is still as close as we can come to giving you a reliable response. I have copied below the question and answer to the inquiry noted above, which should be helpful to you.

One other thing you may do, which is not included in the response copied below, is contact your allergy extract provider to see if there are any data on the specific extracts that they have “in house.”

Thank you again for your inquiry and we hope this response is helpful to you.

Question previously submitted to our website:
When students undergoing AIT come to college, they often bring antigen vials with them or have them shipped to us by their allergist. Does AAAAI have recommendations for procedures when pts. hand carry their vials as well as when they are shipped? Specifically, how long can vials be unrefrigerated? When shipping, is Fed Ex overnight without ice acceptable? Or should ice always be included? I know it is important to prevent freezing, but I have not seen any specific guidelines on the subject of antigen vial transport.

Thank you for your recent inquiry.

Unfortunately there is no definitive answer to your question. Your inquiry is very similar to one which was answered and posted on our website on 9/16/08. For your convenience, I have copied the question and the response below. It speaks indirectly to the questions that you asked, for which there is no consensus, evidence-based response.

However, since that answer was posted, you may take some solace in a more recent article which appeared in the Journal of Allergy and Clinical Immunology (see Reference 1 below). This reference found that there was no effect on Timothy grass allergen extract related to mailing of the vial.

This is the only article that I am aware of that has appeared in the literature since we posted the response, which is copied below. In brief, we cannot give you a definite answer as to how long vials can be refrigerated. However, certainly it is felt that FedEx overnight with ice is acceptable. There is no mandate to include ice on every occasion, and more often than not, it is not included.

Thank you again for your inquiry, which is certainly cogent and important. I am sorry that we cannot give you an evidence-based consensus guideline dealing with these issues, but hopefully the information which we have supplied above will be helpful.

Moore M. The effects of mailing on in vivo and in vitro potencies of standardized Timothy grass extract. Journal of Allergy and Clinical Immunology 2009; 123(2):S230.

Previous Question and Answer posted 9/16/2008:
I am a RN Supervisor in a primary care clinic which administers allergy injections. We do not have allergists on site. The actual allergy clinics send us the solutions via standard mail. On the package it will say to refrigerate immediately but it does not come that way. None of the allergy clinics are able to give us specific info as to how long the solutions can be at room temp or possibly warmer. We want to be sure we are giving solutions that are effective.

Your goals are certainly commendable, and your approach logical. However, I am afraid there may not be a definitive answer for you. There is no question that heating does diminish the allergen content of extracts. I have copied below a scientific abstract from the Journal of Allergy and Clinical Immunology addressing this issue. We have known that this effect occurs, but from a practical standpoint, it may be an impossible problem to solve. It is common practice to mail extracts. Our guidelines (1) recognize this, and state: "In many cases, it might be necessary to administer allergen immunotherapy extract in another physician's office (meaning a physician other than the one who prepared the extract)." Thus, mailing of the extract to another physician is an accepted procedure. This is done realizing that there may be a diminishment of the potency of the extract due to the fact that it is not cooled during the mailing. And, the same guidelines quite clearly state that "allergen immunotherapy extract should be stored at 4 degrees centigrade to reduce the rate of potency loss."

These guidelines review studies looking at the stability of extract. They cite a study undertaken by the American Academy of Allergy, Asthma, and Immunology Immunotherapy and Allergy Diagnostic Committee designed to study the stability of a mixture of standardized extracts in four conditions of storage. They did this with and without intermittent room temperature exposure with extracts diluted in normal saline or human serum albumin. They found different degrees of deterioration depending on the allergen as well as allergen mixture. Thus the standard rate of deterioration could not be calculated.

With these observations in mind, from a practical standpoint, the best advice that we can offer you is to do your best to assure that the extract is refrigerated as soon as you receive it, and maintain it in refrigerated storage until the patient arrives and the shot is administered.

Since data looking at the rate of deterioration varies considerably between extracts and can even vary to a greater extent when allergens are mixed, we cannot tell you with any accuracy at this time how much potency is lost. Of course, it would depend upon the degree of temperature, and we certainly do not know the temperatures during shipping.

Therefore, in reiteration, the best advice that we can give you is to refrigerate the extract immediately, and keep it under refrigerated storage until the arrival of the patient and the shot is administered. Then re-store it immediately.

I am sorry that I cannot give you more definitive data, but such simply does not exist at this time. Thank you again for your inquiry.

1. Cox L, et al. Allergen immunotherapy: a practice parameter, second update. J Allergy Clin Immunol, September 2007; 120(3):S47

Phil Lieberman, M.D.

Ch 9 AAAAI Allergen Immunotherapy Extract Preparation Manual (pages 30 and 31)