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Importance of Cross-Reactivity Closely related allergen species often exhibit some degree of cross-reactivity. In general, plant species within the same taxonomic family may be substantially, though not completely, cross-reactive. Additionally, there are several allergenic proteins which are common across unrelated species known as “pan-allergens”. For some patients, these proteins can generate an IgE immune response… read more

Potency Labeling The biologic strength (potency) of an allergenic extract can be expressed in a variety of ways. In general, all allergenic extracts are divided into 2 categories: Standardized (BAU /AU) The FDA has mandated standardization testing for a limited number of extracts. The purpose of standardization is to minimize the amount of variability between… read more

Source Material Collection The manufacture of an allergenic extract begins with the identification and procurement of a natural source material. 1 Source material collection is a process that results in a relatively pure sample of allergenic substances (e.g., pollen, dander/epithelium, fungal cultures, whole insects, foods, etc.). A successful collection of allergenic material can depend on… read more

Analytical Method – ID50EAL (“IDEAL 50”) Standardized potency values were established by a skin test titration study (ID50EAL) using a limited number of patients. “ID50EAL” is an acronym for “Intradermal Dilution for 50 mm sum of Erythema determines the bioequivalent ALlergy units.” This study measured the size of the erythema in allergic patients receiving a… read more

Positive & Negative Controls Postive Control – Histamine Since a major physiological component of the allergic response is histamine, it is important to use a histamine reagent to confirm that the patient’s skin has sufficient reactivity to properly interpret the skin test results. In line with this rationale, the histamine positive control can help determine… read more