Activity units for allergen extracts


Dr W. D. Brighton, National Institute for Biological Standards and Control, Holly Hill, Hampstead, London NW3 6RB.


The two present systems of units for the strength of allergen extracts, Noon and p.n.u. are both unsatisfactory. A new activity unit, based on skin prick in humans, is described, and its relationship to in vitro tests is explored. Potency limits for provocation materials used for skin prick tests are suggested.