A comparison of methods for the detection of candida antigens. Evaluation of a new latex reagent

The sensitivity of various serological techniques for the detection of C citalbicans cytoplasmic antigen (Ag) in buffer and serum diluents was compared, with special reference to variations of the ELISA method and a new microtitre latex particle agglutination (MLA) test. Of the assays evaluated, immunodiffusion, counterimmunoelectrophoresis and slide latex particle agglutination (SLA) were the least sensitive. ELISA tests were more sensitive (50–150 ng/ml Ag in buffer) although sensitivity decreased in serum or heat-inactivated serum (HIS) (250 ng/ml-4 μg/ml). The new MLA test had better sensitivity (16 ng/ml Ag in buffer) than any of the ELISA tests and was unaffected by the presence of serum or HIS (2.5 and 20 ng/ml Ag respectively). MLA seems worthy of further evaluation as an alternative to ELISA for use in antigen detection systems in general and for the serodiagnosis of systemic candidosis in particular.