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TSH Antibody
Test Code36577
CPT Codes
83519
Preferred Specimen
1 mL serum
Minimum Volume
0.5 mL
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 14 days
Refrigerated: 14 days
Frozen: 28 days
Refrigerated: 14 days
Frozen: 28 days
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Plasma
Methodology
Radioimmunoassay (RIA)
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by FDA. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: Sun, Wed; Report available: 4-8 days
Clinical Significance
This test may help identify thyroid stimulating hormone (TSH) autoantibodies. When the serum TSH level is discordant with clinical manifestations or other test results (eg, markedly elevated TSH with normal free triiodothyronine and free thyroxine levels), this test may be used to determine if TSH autoantibodies are the cause of discordance.
TSH autoantibodies can bind TSH to form a macromolecule (macro-TSH) that has low biological activity but interferes with TSH immunoassays [1]. Interference by macro-TSH may be screened by polyethylene glycol precipitation and gel filtration chromatography [1].
Anomalous TSH levels may also be caused by a range of interfering substances, such as biotin, heterophilic antibodies, and antibodies to streptavidin and ruthenium [1].
Other conditions that may result in elevated TSH levels with normal free triiodothyronine and free thyroxine levels include subclinical hypothyroidism, poor adherence to (or malabsorption of) thyroxine therapy, certain drugs (eg, amiodarone), nonthyroidal illness recovery phase, and TSH resistance [2].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Favresse J, et al. Endocr Rev. 2018;39(5):830-850.
2. Gurnell M, et al. Clin Endocrinol (Oxf). 2011;74(6):673-678.
TSH autoantibodies can bind TSH to form a macromolecule (macro-TSH) that has low biological activity but interferes with TSH immunoassays [1]. Interference by macro-TSH may be screened by polyethylene glycol precipitation and gel filtration chromatography [1].
Anomalous TSH levels may also be caused by a range of interfering substances, such as biotin, heterophilic antibodies, and antibodies to streptavidin and ruthenium [1].
Other conditions that may result in elevated TSH levels with normal free triiodothyronine and free thyroxine levels include subclinical hypothyroidism, poor adherence to (or malabsorption of) thyroxine therapy, certain drugs (eg, amiodarone), nonthyroidal illness recovery phase, and TSH resistance [2].
The results of this test should be interpreted in the context of pertinent clinical and family history and physical examination findings.
References
1. Favresse J, et al. Endocr Rev. 2018;39(5):830-850.
2. Gurnell M, et al. Clin Endocrinol (Oxf). 2011;74(6):673-678.
