/sup 125/I-radioimmunoassay for unconjugated estroil in serum of pregnant women
An /sup 125/I-radioimmunoassay is described which measures unconjugated estriol in the serum of pregnant women. Estriol is extracted into ethyl acetate/hexane, an aliquot is evaporated, and the residue is redissolved in phosphate buffer. The sample is incubated with tracer and antibody at 37/sup 0/C for 15 min and then at 4/sup 0/C for 1 h and 45 min. The antibody-bound fraction is then precipitated with polyethylene glycol and isolated by centrifugation. Because the antigen-antibody complex is stable in the presence of polyethylene glycol, the separation steps are not influenced by timing. Extraction recovery of /sup 3/H-labeled estriol added to a pool of sera from pregnant women averaged 96.7% (SD = 1.3, n = 10). Estriol-supplemented (5, 10, and 20 ..mu..g/liter) serum from men, carried through the entire procedure, showed analytical recovery ranging from 94 to 106%. Structurally analogous steroids normally present in serum of pregnant women exhibit negligible cross reactivity. Day-to-day precision (CV) is 13.3% (3.1 ..mu..g/liter), 6.4% (7.6 ..mu..g/liter), and 5.6% (21.4 ..mu..g/liter) for n = 21. The current reagent cost (about 17 cents per tube), and a total procedural time, including counting, of 5.5 h make this an acceptable assay for routine use.
- Research Organization:
- Swedish Hospital Medical Center, Seattle
- OSTI ID:
- 7053622
- Journal Information:
- Clin. Chem.; (United States), Journal Name: Clin. Chem.; (United States) Vol. 24:7; ISSN CLCHA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
62 RADIOLOGY AND NUCLEAR MEDICINE
ACCURACY
ANIMALS
ANTIGEN-ANTIBODY REACTIONS
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BLOOD
BLOOD PLASMA
BODY FLUIDS
COST
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ESTRANES
ESTRIOL
ESTROGENS
FEMALES
HORMONES
HYDROXY COMPOUNDS
IMMUNE SERUMS
INTERMEDIATE MASS NUCLEI
IODINE 125
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LABELLED COMPOUNDS
MAMMALS
MAN
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PREGNANCY
PRIMATES
RADIOASSAY
RADIOIMMUNOASSAY
RADIOISOTOPES
STEROID HORMONES
STEROIDS
TRACER TECHNIQUES
VERTEBRATES
WOMEN