Abstract
A sensitive radioimmunoassay for measurements of 3,3'-5'-triiodothyronine (reverse T3, rT3) in small amounts of unextracted serum is described. The interference of rT3 binding proteins in serum was precluded by addition of 8-anilino-1-naphthalene sulphonic acid (ANS). The cross reaction of T4 with the rT3 anti-serum varied with the concentration of T4 in the samples. At 50 per cent inhibition of [125I]rT3 binding, the T4 cross reaction was 0.075% (mol/mol). All values were corrected for T4 cross reaction. By the present method total rT3 averaged 0.37 nmol/l in thirty-two normal subjects. Higher values (0.81-1.98 nmol/l) were obtained in seventeen thyrotoxic patients, while the rT3 was very low (less than or equal to 0.046 nmol/l) in ten patients with severe primary hypothyroidism. A modification of the total rT3 assay was used for measurements of rT3 in serum dialysates (free rT3). The sensitivity was 0.46 pmol/l. This sensitivity did not allow detection of free rT3 in all normal subjects.
Original language | English |
---|---|
Journal | Scandinavian Journal of Clinical & Laboratory Investigation |
Volume | 37 |
Issue number | 8 |
Pages (from-to) | 735-9 |
Number of pages | 5 |
ISSN | 0036-5513 |
Publication status | Published - Dec 1977 |
Externally published | Yes |
Keywords
- Adult
- Cross Reactions
- Dialysis
- Female
- Humans
- Male
- Radioimmunoassay
- Thyroxine
- Triiodothyronine