Calcium Determinations in Kinetic Studies

[摘要] Published reports of a fraction of blood calcium that does not equilibrate with a tracer has created a controversy that challenges the validity of much calcium kinetic data. To resolve this controversy, calcium specific-activity measurements were made on blood and urine samples in vitro and in vivo. The experiments were designed to provide maximal sensitivity for demonstrating non exchangeable calcium. A new and accurate method for urine calcium determinations was used. The results demonstrated complete equilibration between tracer and stable blood calcium. We suggest that published evidence of non exchangeable calcium in blood and urine is erroneous due to inaccurate urine calcium determinations.

[学科分类] 过敏症与临床免疫学