A new rapid semi-quantitative enzyme immunoassay suitable for determining immunity to tetanus.

A sensitive enzyme immunoassay for rapidly assessing a patient's state of immunity to tetanus is described. The test, which uses 50 microliter sample of blood, plasma or serum, is done in a capillary tube and, by comparison with two adjacent reference tubes containing standardised sera, places immunity to tetanus in one of three categories--low-negative (less than 0.01 IU/ml), intermediate (0.01-1.28 IU/ml) or high (greater than 1.28 IU/ml). In a study of 90 clinical specimens assayed both by toxin neutralisation bioassay and capillary enzyme immunoassay the enzyme immunoassay accurately assessed the state of immunity to tetanus of the patients concerned.