SENSITIVE TIME-RESOLVED FLUOROIMMUNOASSAY OF SALMON-CALCITONIN

A two-site assay was developed by use of the ''dissociation and enhanc ement lanthanide fluoroimmunoassay'' (DELFIA) technique for determinat ion of salmon calcitonin (SCT) in serum after administration to osteop orotic patients. Polyclonal antibodies were produced in rabbits immuni zed with SCI coupled to ovalbumin. After affinity purification, the an tibodies were used both as immobilized capture antibodies and as Eu-ch elate-labeled signal antibodies. A Sensitive assay with a detection li mit of 1.1 pmol/L was achieved, and no cross-reaction with human calci tonin was observed. The intra- and interassay CVs were <12% (n = 10) a nd <15% (n = 4), respectively. Analytical recovery of SCT added to ser um was 91% +/- 3% (mean +/- SD, n = 4). SCT was measurable in all the samples from eight osteoporotic patients after subcutaneous SCT admini stration. We conclude that this new sensitive and specific two-site DE LFIA can reliably measure SCT in serum.