In the absence of the classical triad of mycetoma, the demonstration of significant antibodies titers against the causative organism may be of diagnostic value. Serodiagnosis is of a great help in identification and classification of the various organisms, which is an essential prerequisite for medical treatment, and is mandatory for the follow-up of these patients.
It has many advantages over the culture and histopathological techniques, as both require surgical biopsy, which may enhance the spread of the organism. The common serodiagnostic test for mycetoma are the counter-immuno-electrophoresis (CIE) and Enzyme linked immunosorbent assay (ELISA). (CIE)
It distinguishes between eumycetoma and actinomycetoma and between Actinomycetes themselves, but cross reactivity between A. madurae and A. pelletierii is quite common. However, it is time consuming and the preparation of the antigens take a considerable time.
Enzyme linked immunosorbent assay (ELISA) was used in the diagnosis of mycetoma. It appeared to be a sensitive test for the detection of antibodies, however the high sensitivity of the test makes the cross reactivity unavoidable. ELISA may be a useful tool in community studies as sero-epidemiological survey could give valuable information on the distribution and prevalence of exposure to mycetoma.
Recombinant based ELISA performed with pure antigens of M. mycetomatis, had detected translationally controlled tumour protein (TCTP) and luminex assays based on TCTP, fructose-bisphosphatealdolase (FBA) and pyruvate kinase (PK). Although patients had higher antibody levels, antibodies were detected in healthy controls making these techniques unsuitable as diagnostic tools.
It is clear that these serodignostic tests have many limitations that include tedious and lengthy preparation of antigens, the antigens are crude and not standardized hence cross reactivity between different mycetoma causative organisms is found.