An improved assay for human tetanus anti-toxin and its use in the accession of human plasma for the production of high-titre tetanus immunoglobulin.

ABSTRACT

A simplified passive haemagglutination (PHA) screening test, an improved quantitative PHA assay, and a stable test cell preparation are described, as well as a comprehensive testing strategy which have been used in concert at this Service over the past 10 years for the successful accession of high-titre tetanus anti-toxin (TAT) plasma for fractionation into human tetanus immunoglobulin (HTIG). The sequential deployment of the screening and quantitative assays, has permitted large numbers of donors to be screened quickly and economically, and has helped establish a significant core of regular donors with high TAT levels. The assays have proven to be highly sensitive and specific and relatively simple to perform, while the coated cells are inexpensive and easily prepared. Approximately 20% of donors screened from the Sydney metropolitan area had TAT levels of 3 IU/ml or greater.