[The use of passive hemagglutination with turkey erythrocytes for the effective prevention of tetanus in wounded patients].

The passive haemagglutination assay is at present the most common method available for evaluating tetanus antibody levels. We recently developed a modification of the technique of HA by Mai and Rosin using turkey red blood cells (TRBC-HA) instead of sheep red blood cells (SRBC-HA). TRBC-HA assay seems to offer the advantages of being more sensitive and easier to perform than the SRBC-HA method. More important, with the TRBC-HA assay, we found that the HA values greater than 0.5 H.U./ml always correspond to NT values greater than 0.01 IU/ml. Therefore this value (0.5 H.U./ml) was chosen as a discriminating level between protected and non protected persons. On this rationale base we have tested sera from injured persons in order to individualize a single prophylactic treatment under a rationale guideline against the alternative of a blind intervention under anamnestic basis. Among 437 persons tested 248 did not remember if they had been vaccinated or not. According to the anamnestic basis all these persons should require injection of human antitetanus Ig plus a basic course of vaccination. On the contrary antitetanus antibody levels monitored by TRBC-HA assay indicate that 132 were protected and did not require any treatment; 79 were partially protected and required a boosting of tetanus toxoid and only 37 were not protected and needed human antitetanus IgG plus a complete course of vaccination. These results underline the necessity of monitoring a single person for antitetanus antibodies in order to prevent both under or over evaluation of their tetanus immune status.