Highly sensitive radioimmunoassay for chorionic gonadotropin in human urine. [/sup 125/I tracer technique]
The value of RIAs that measure hCG levels in human urine has been limited principally because of cross-reactivity with human LH. Recently, antisera generated to antigenic determinants on the intact hCG..beta.. subunit and its carboxyl-terminal peptide have been shown to exhibit substantially reduced human LH cross-reactivity. To take maximal advantage of these antisera and to minimize interference by nonspecific substances in urine, a procedure for extracting and concentrating hCG from 24-h urine samples was developed. The procedure involves preparation of a standard kaolin-acetone urine concentrate and adsorption of the hCG in the concentrate to Concanavalin A covalently linked to agarose for purification and subsequent RIA. In urine samples obtained from patients with gestational trophoblastic disease, there was a direct correlation between hCG levels measured by RIA and those estimated by mouse uterine weight bioassy. In individual subjects, hCG levels were determined in serum and urine obtained the same day. When hCG was clearly detectable in the serum at levels greater than 1 ng/ml, the quantity of hCG measured in the urine concentrate exceeded 500 ng/24 h. The concentrates prepared from the urine of normal persons contained an hCG-like glycoprotein substance with antigenic determinants similar to those of the carboxyl-terminal peptide of hCG..beta... As the range of hCG immunoreactivity measured in the urine concentrates of normal subjects was 6 to 52 ng/24 h, specific and sensitive detection of urinary hCG could be accomplished in patients whose sera contained hCG undetectable by conventional RIA. Partial purification and concentration of urinary hCG by this procedure with subsequent RIA provides a sensitive and reliable method for detecting hCG in urine.
- Research Organization:
- National Insts. of Health, Bethesda, MD
- OSTI ID:
- 6540984
- Journal Information:
- J. Clin. Endocrinol. Metab.; (United States), Vol. 47:4
- Country of Publication:
- United States
- Language:
- English
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GONADOTROPINS
RADIOIMMUNOASSAY
SENSITIVITY
BLOOD SERUM
IMMUNE REACTIONS
IMMUNE SERUMS
IODINE 125
TRACER TECHNIQUES
URINE
BETA DECAY RADIOISOTOPES
BIOLOGICAL MATERIALS
BIOLOGICAL WASTES
BODY FLUIDS
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
HORMONES
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
NUCLEI
ODD-EVEN NUCLEI
PEPTIDE HORMONES
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RADIOASSAY
RADIOISOTOPES
WASTES
550601* - Medicine- Unsealed Radionuclides in Diagnostics