Other Parameters

Serum

Samples can be kept up to 14 days at 2°C – 8°C or stored at -20°C. Repeated freezing and thawing should be avoided. Lipaemic or grossly haemolysed serum samples as well as plasma should not be used in the assay. When required, thaw test sera at room temperature and mix gently to ensure homogeneity.

• Negative      <1 U/L
• Grey zone    1,0 -2,0 U/L
• Positive        >2,0 U/L

Human

Autoantibodies including rheumatoid factor, autoantibodies of thyroglobulin, thyroid peroxidase, ds DNA and acetylcholine receptor do not interfere in the assay. Furthermore, no effect is observed with human LH (up to 10 U/ml), human TSH (up to 30 U/ml), and human FSH (up to 70 U/ml).

The TSH receptor autoantibody 2nd generation test is an ELISA for the quantitative determination of autoantibodies against human TSH receptor in human serum. (B. Rees Smith, Thyroid 2004). The method is based on a porcine-TSH-Receptor and TSH labeled with Biotin.
In hyperthyroidism due to thyroid autonomy (Graves’ disease) is induced by autoantibodies directed against the TSH receptor. Therefore, TSH receptor autoantibodies are detectable in patients suffering from untreated Graves’ disease.
Determinations of TSH receptor autoantibodies are clinically used to confirm the diagnosis of Graves’ disease and to differentiate the disease from disseminated autonomy of the thyroid. Around 98% of the patients with Graves’ disease react positively in the TSH receptor antibody assay.
The determination of TSH receptor autoantibodies in the course of Graves’ disease has predictive value and serves as an important tool in therapy monitoring. High levels of TSH receptor autoantibodies after longer-term thyrostatic therapy in patients with Graves’ disease indicate an increased risk for recurrence. The measurement of TSH receptor autoantibodies may also be helpful in the field of ophthalmology as many patients showing symptoms of Graves’ disease first consult an eye doctor.