Radioimmunoassay of ''free thyroxin'' in dried blood spots on filter paper - preliminary observations on the effective differentiation of subjects with congenital hypothyroidism from those with subnormal thyroxin-binding globulin and normal subjects

Journal Article · Mon Mar 01 00:00:00 EST 1982 · Clin. Chem. (Winston-Salem, N.C.); (United States)

OSTI ID:5031520

Mizuta, H; Miyai, K; Ichihara, K; Amino, N; Harada, T; Nose, O; Tanizawa, O

In this sensitive, simple method for measuring ''free thyroxin'' (FT/sub 4/) in eluates of dried blood spots on filter paper by use of a radioimmunoassay kit (Amerlex Free T/sub 4/ RIA), the measurable range of FT/sub 4/ is 1.8 to 57 ng/L (equivalent to the concentration in serum), or 7 to 237 fg/tube. The mean coefficients of variation for within assay-within spots, within assay-between spots, and between assays were 5.3%, 5.0%, and 6.2%, respectively. FT/sub 4/ in blood spotted on filter paper is stable for at least a month when dried and kept at either -20/sup 0/C, 4/sup 0/C, room temperature (about 25/sup 0/C), or 37/sup 0/C. The results for FT/sub 4/ in dried blood spots correlated closely with the free-T/sub 4/ concentration in serum (r = 0.99). The method can be used to differentiate cases of primary and secondary hypothyroidism from normal subjects and those with subnormal thyroxin-binding globulin. This method may be useful in screening for congenital hypothyroidism, because sample-retesting is not necessary.

• Research Organization: Osaka Univ., Japan
• OSTI ID: 5031520
• Journal Information: Clin. Chem. (Winston-Salem, N.C.); (United States), Vol. 28:3
• Country of Publication: United States
• Language: English

Related Subjects

62 RADIOLOGY AND NUCLEAR MEDICINE
CONGENITAL DISEASES
DIAGNOSIS
HYPOTHYROIDISM
THYROXINE
RADIOIMMUNOASSAY
BLOOD
BLOOD SERUM
PATIENTS
PREGNANCY
AMINO ACIDS
BIOLOGICAL MATERIALS
BODY FLUIDS
CARBOXYLIC ACIDS
DISEASES
ENDOCRINE DISEASES
HORMONES
ISOTOPE APPLICATIONS
MATERIALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC IODINE COMPOUNDS
PEPTIDE HORMONES
RADIOASSAY
THYROID HORMONES
TRACER TECHNIQUES
550601* - Medicine- Unsealed Radionuclides in Diagnostics