[Sensitivity and specificity of the RAST (radioallergosorbent test) in biological diagnosis of the hydatidosis (author's transl)].

The radioallergosorbent test (RAST) for specific IgE antibodies to Echinococcus granulosus was compared with other immunological methods in regard to sensitivity, specificity and its use as a diagnostic aid for hydatid disease. Sera used were from patients with active hydatidosis proved surgically, from persons operated for hydatidosis during the previous 2-10 years and from patients with other parasitic diseases or healthy subjects. Results with enzyme-immuno assay (ELISA), indirect haemagglutination (IHA), counter-immunoelectrophoresis (CIEP) and skin test were compared with those with RAST. The percentage of positive RAST reactions (81.2%) among the patients with active hydatidosis was slightly lower than the percentage of positive ELISA (90.6%), IHA (90.6%) and skin test (87.5%) and was superior to CIEP (75%). Among the patients with previous hydatidosis, the RAST was negative in 90% of case, whereas other serological tests were positive in a considerable proportion of cases (ELISA test, 80%; IHA test, 40%; CIEP test, 40%; skin test, 60%). A high percentage (50%) of false positive RAST reactions have been observed in sera from patients infested with other parasites. Results indicated that the RAST for IgE antibodies not be used as the only method for diagnosis of hydatidosis, but it may be employed, if serological data obtained before surgery are available for comparison, for evaluate the results of surgery and to clarify the prognosis.