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- Aspergillosis -
9/10/04 re: Availability and procedure for aspergillus skin testing MD ordered Aspergillus skin test, and insisted to provide to patient ASAP. I am having difficulty finding information regarding this skin test. How can we obtain Aspergillus extract and how is this skin test supposed to be done. Could you please send me some info?
You did not specify the clinical indication for which aspergillus (Asp) skin testing is needed, possibly because the physician did not provide such information. If the need is to investigate the possibility of allergic broncho-pulmonary aspergillosis (ABPA), one would want a skin testing extract of Asp fumigatus. Such materials are available as relatively crude extracts from allergy skin test material providers such as the Greer Labs in Lenoir, NC or Hollister-Stier Labs in Spokane, WA. The technique involves intradermal injection of 0.03 ml of the Asp fumigatus extract in the forearm skin and observation for a significant wheal and flare response at the site 20 minutes later. The site is also inspected at 6-8 hours for a “late phase” inflammatory reaction.
Almost all adult patients with ABPA have a significant skin test whealing response at 20 minutes, so a negative response is strong evidence against a diagnosis of ABPA. However, positive skin test responses at 20 minutes are seen in a significant minority of asthmatics and other individuals with allergic respiratory disorders. Thus, a positive skin test by itself does not prove that the patient has ABPA.
The late phase skin test reaction to Asp fumigatus skin testing occurs less commonly in ABPA (about 70-80% of cases) but may add some additional evidence for the presence of ABPA. However, I should mention that the performance of these skin tests and interpretation of the responses requires experience. Therefore, I suggest that the requesting physician obtain consultation with a board-certified allergist. Such a specialist may already have a supply of the Asp fumigatus skin test material.
