Evaluation of a dipstick test (Allergodip-Latex) for in vitro diagnosis of natural rubber latex allergy.

BACKGROUND IgE-mediated hypersensitivity to latex has been recognized as an increasing health problem with far-reaching consequences for patients, regarding both their occupational situation and safety in medical care. Therefore, a correct diagnosis of natural rubber latex (NRL) allergy is essential. The purpose of the study was to evaluate sensitivity and specificity of several established diagnostic methods for NRL allergy (in vitro assays and skin prick test) in relation to a new semiquantitative dipstick test (Allergodip-Latex, Allergopharma) as a screening test for NRL allergy. METHODS Data obtained with quantitative assays including Pharmacia CAP System(FEIA), DPC-AlaSTAT and Magic Lite were compared with the dipstick test results in latex-sensitized (n = 151) and nonsensitized persons (n = 232). In addition these in vitro findings were related to clinical symptoms after exposure to latex and skin prick test results with a panel of different latex allergen extracts. RESULTS When comparing sensitivity and specificity of all in vitro assays relative to skin prick test results the Pharmacia CAP System (FEIA) had the highest sensitivity in the range of 90%. Sensitivity of the other in vitro assays was in the range of 73.7-74.9%, specificity varied from 85.3 to 89.8%. A diagnostic standard was defined in terms of at least three corresponding test results out of all diagnostic methods (in vitro assays and skin prick test). The sensitivity and specificity of each diagnostic test were determined relative to this diagnostic standard. Hereby the Allergodip test results showed a sensitivity of 91% and a specificity of 93%. CONCLUSION The dipstick test results are in line with the data of the other in vitro assays. In contrast to other in vitro assays the dipstick test requires no further laboratory equipment and is easy to perform.