Use of filter paper discs as substrate for collection and storage of blood samples for screening of anti-tetanus toxoid antibodies.

A sensitive and specific enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to tetanus in dried blood samples spotted on filter paper discs has been developed. A good correlation was found between the two methods, filter paper disc assay and direct blood assay (r = 0.91). The specificity of the test was determined by a competitive inhibition assay using goat anti-tetanus-toxoid antibodies coupled to horseradish peroxidase. The interassay coefficient of variation is 10-12%. The antibodies were measurable until 4 months of storage of filter paper discs at room temperature (25 degrees C). This procedure is useful for mass screening of anti-tetanus antibodies using dried blood samples on filter paper discs.