In-house preparation and evaluation of (125)I-histamine progesterone tracer for radioimmunoassay of progesterone.

The progesterone tracer for the development of in-house radioimmunoassay was prepared in two steps clearly described. First, activation of 11α-hemisuccinate progesterone (progesterone-11 α HS) and labeling of histamine with (125)I, and second, conjugation of activated 11α-HS progesterone with iodinated histamine. The purification of the tracer was carried out by gel filtration on Sephadex G-25. The radiochemical purity of purified the tracer was 95%. The maximum binding using solid phase (coated tubes) reached 41% and the non specific binding didn't exceed 5%. The tracer stored at different temperatures 10°C and -6°C was stable during 12 weeks. The skim milk provided assay better sensitivity (0.22 ng/mL) than serum (0.28 ng/mL).