Rapid detection of fungal α-amylase in the work environment with a lateral flow immunoassay

Background: Occupational allergen exposure assessment usually requires airborne dust sampling at the worksite followed by dust extraction and enzyme immunoassay (EIA) analysis at the laboratory. Use of semiquantitative lateral flow immunoassays (LFIAs) may allow a more rapid detection procedure with direct on-site demonstration of a bioallergen exposure hazard. Objective: In a field study, we evaluated a recently developed LFIA for fungal alpha-amylase, an important bakery allergen. Methods: Airborne and surface dust (wipe) samples and samples from flours and baking additives used at the workplace were collected in 5 industrial bakeries and tested in the LFIA for fungal amylase. For comparison, amylase was measured in sample eluates with the reference EIA method. Results: Sensitivity of the LFIA was 1 to 10 ng/mL, and of EIA, similar to 25 pg/mL. In LFIA, most flour. samples, 84% of wipe samples, 26% of personal airborne dust, and none of the 26 ambient air dust samples produced a visible reaction. Wipe samples from dough-making areas and flour samples gave the strongest reactions. All extracts with > 5 ng allergen per milliliter showed a positive LFIA reaction. Conclusion: The LFIA for fungal amylase is an easy and rapid method to demonstrate the allergen directly at the worksite in less than 10 to 20 minutes. Similar LFIA methods may be used for other occupational allergens in other work environments. Clinical implications: Lateral flow immunoassays for occupational allergens may be of great value in occupational hygiene surveys to demonstrate directly to workers and supervisors the hazards of work-related bioallergen exposure.