Biological Assay of Diphtheria Antitoxin
The potency of diphtheria antitoxin is determined by comparing the dose necessary to
protect guinea-pigs or rabbits against the erythrogenic effects of a fixed dose of the
Standard Preparation of diphtheria antitoxin necessary to give the same protection. For
this purpose, a suitable preparation of diphtheria toxin is required to be used as a test
toxin. The test dose of the toxin is determined in relation to the Standard Preparation. The
potency of the preparation being examined is then determined in relation to the Standard
Preparation using the test toxin.
The potency of diphtheria antitoxin is determined by comparing the dose necessary to
protect guinea-pigs or rabbits against the erythrogenic effects of a fixed dose of the
Standard Preparation of diphtheria antitoxin necessary to give the same protection. For
this purpose, a suitable preparation of diphtheria toxin is required to be used as a test
toxin. The test dose of the toxin is determined in relation to the Standard Preparation. The
potency of the preparation being examined is then determined in relation to the Standard
Preparation using the test toxin.