Duration of streptokinase-streptodornase (SK/SD) protency for delayed hypersensitivity skin testing

During of potency for SK/SD solutions used as recall antigens in delayed hypersensitivity skin testing had not been determine. In a study of 50 normal subjects over a one-year period it was found that antigenicity diminished with time. At four months, however, there was no evidence of impaired potency at any of the dilutions tested. Authors suggest that reconstitution of SK/SD be made every three months when kept at room temperature and that increasing strengths be applied beginning at 4/1 units.