Testing for cattle allergy: modified diagnostic cutoff levels improve sensitivity in symptomatic claw trimmers.
BACKGROUND
The diagnosis of cattle-related sensitization is complicated by the variability and complexity of cattle allergen extracts.


OBJECTIVE
To evaluate a modified diagnostic procedure leading to more accurate results especially in the early phase of sensitization.


METHODS
We tested 27 claw trimmers with and 65 without cattle-related symptoms using two commercially available cattle allergen extracts. We also used a self-prepared cattle allergen mix designed to represent the full spectrum of cattle allergens from a typical agricultural workplace.


RESULTS
More than 50% of symptomatic claw trimmers showed negative test results with commercial extracts and a sensitization cutoff point of 0.35 kU/l. In contrast, with the self-prepared cattle allergen mix, positive results were observed for almost all of them. Evaluating the results of the commercial test kits at different cutoff levels, we found an ideal cutoff point to improve the sensitivity at 0.2 kU/l.


CONCLUSIONS
Additional tests with self-made cattle hair extracts can help to bridge the diagnostic gap seen in patients showing cattle-related symptoms, but negative results in commercially available tests. For early-stage sensitization screening, we propose to lower the cutoff level indicating sensitization to 0.2 kU/l.
Heutelbeck
Astrid
A
Institute for Occupational and Social Medicine, University of Göttingen, Waldweg 37, 37037 Göttingen, Germany. aheutel@gwdg.de
Dik
Natalja
N
Hallier
Ernst
E
Zuberbier
Torsten
T
Bergmann
Karl-Christian
KC
D000328:Adult; D000485:Allergens / Q000276:immunology / Q000302:isolation & purification*; D000818:Animals; D002417:Cattle; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D005858:Germany; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis* / Q000276:immunology; D015151:Immunoblotting; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D012680:Sensitivity and Specificity; D055815:Young Adult
D000485:Allergens; D007073:Immunoglobulin E