Evaluation of the indirect hemagglutination assay for antibodies detectionin aspergillosis diagnosis

Introduction. Aspergillus infection may lead to various clinical patterns a ccording to the immune status of the patients. The diagnosis of aspergillos is may be difficult to achieve in some situations, particularly in immunosu ppressed patients, and usually results from the association of clinical, ra diological and biological features. Detection of specific antibodies remain s of great value in diagnosing aspergilloma or allergic bronchopulmonary as pergillosis in immunocompetent patients. Objectives. To evaluate the performances of indirect hemagglutination for A spergillus antibody detection and to determine the place of this method in the serologic diagnosis of aspergillosis. Methods. We compared three commercially available assays for the detection of Aspergillus antibodies: hemagglutination, electrosyneresis and immunoele ctrophoresis which was the reference test. The evaluation of the assays com prised sensitivity, specificity, cost and feasibility. Results. One hundred and seventy six sera were analyzed with the three assa ys: 39 were collected from patients with aspergillosis (different patterns) , 137 from controls. Sensitivity was 32 % with the hemagglutination assay ( threshold 1/640), 64% with the electrosyneresis assay and 92 % with the imm unoelectrophoresis assay. Specificity was 93 % with the hemagglutination as say, 100 % with the electrosyneresis and the immunoelectrophoresis assays. When the threshold of the hemagglutination assay was lowered at 1/160 the s ensitivity and specificity became 76 % and 88 % respectively. The feasibili ty was better with the hemagglutination assay and it was less time-consumin g than the other methods. Conclusion. These results suggest that the hemagglutination assay could be performed for the detection of Aspergillus antibodies if the threshold is l owered at 1/160 and the positive results are confirmed with the immunoelect rophoresis assay.