SOME FACTORS AFFECTING THE DETECTION OF LONG-ACTING THYROID STIMULATOR PROTECTOR USING THE McKENZIE BIOASSAY

Abstract

SUMMARY The long-acting thyroid stimulator (LATS) protector may be detected by its property of blocking the binding of LATS to LATS absorbing activity (LAA). This study confirmed that the sensitivity of LATS protector detection was largely determined by the choice of reference mixture of LATS and LAA. Optimal sensitivity was achieved when: (a) the reference concentration of LATS activity gave a response at the upper end of the linear part of the dose–response curve; (b) the reference LATS-containing serum required a minimum of LAA for LATS binding; (c) the reference LAA preparation was free of thyroglobulin; (d) the concentration of LAA in the reference mixture was that which almost abolished the response to the reference concentration of LATS; (e) the reference LAA preparation was incubated with LATS protector before the addition of the reference LATS.