MEASUREMENT OF DIPHTHERIA AND TETANUS ANTITOXIN IN BLOOD-SAMPLES COLLECTED ON FILTER-PAPER DISKS

Large-scale surveys of immunity to vaccine-preventable diseases may be limited by the inconvenience and expense involved in collection of bl ood by venepuncture. An alternative method of collecting blood on filt er paper for measurement of immunity to diphtheria and tetanus is desc ribed. The precut filter disks (Elisadiscs), originally developed for serological diagnosis of disease in pigs, have advantages over previou sly described methods in that they allow safe handling of minimal volu mes of blood (5 mu 1) which can be conveniently quantified. To compare values obtained by venepuncture and fingerprick, paired samples were collected from 60 subjects and diphtheria and tetanus antitoxin concen trations were measured by ELISA. There was no significant difference d etected between samples collected by the two methods. The results sugg est that Elisadiscs are a reliable alternative to venepuncture for mon itoring immunity to diphtheria and tetanus and would be useful for sam ple collection in remote areas and from children.