This blocker it should be used to avoid interference in an IgG/IgM indirect assay when a recombinant antigen produced in Pichia pastoris is used for Ab detection in mammalian sera. Occasionally, the anti-cross-reactive carbohydrate determinants (anti-CCD) antibodies are present in human and animal sera due to previous immunization against pathogenic fungi such as Candida albicans, the most common cause of opportunistic fungal diseases in humans. These pathogenic fungi share the same type of glycosylation with Pichia pastoris. Therefore, these anti-CCDs should be pre-absorbed to avoid false positive results.