Thyroid Stimulating Hormone

Test Code

TSH

CPT Codes
84443

Preferred Specimen

Serum (gold or red top tube)

Minimum Volume

0.5 mL

Transport Container

Serum (gold or red top) tube

Transport Temperature

Room Temperature or Refrigerated

Specimen Stability

Room Temperature - 1 day; Refrigerated - 7 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Turbidity, Quantity Not Sufficient, IV contamination

Methodology
Chemiluminescence

Setup Schedule

Daily upon receipt

Report Available

Upon completion of analysis

Limitations

Thyroid hormone autoantibodies in samples may cause interference with this test. Results which are inconsistent with clinical observations indicate the need for additional testing. The performance of this test has not been established using neonatal specimens.

Reference Range

0.465 - 4.68 mIU/mL

Clinical Significance

TSH secretion by the anterior pituitary is controlled by thyrotropin releasing hormone, a tripeptide produced by the hypothalamus. TSH stimulates the production of thyroxine (T4) and triiodothyronine (T3) by the thyroid gland. The circulating free fractions of T4 and T3 in turn regulate the secretion of TSH by a negative feedback mechanism at the pituitary and possibly the hypothalamus. The diagnosis of overt hypothyroidism by the finding of a low total T4 or free T4 concentration is readily confirmed by a raised TSH concentration. Measurement of low or undetectable TSH concentrations may assist the diagnosis of hyperthyroidism, where concentrations of T4 and T3 are elevated and TSH secretion is suppressed. TSH tests with high levels of precision and functional sensitivity claims of 0.01–0.02 mIU/L have been termed “third generation” tests. These have the advantage of discriminating between the concentrations of TSH observed in thyrotoxicosis, compared with the low, but detectable, concentrations that occur in subclinical hyperthyroidism.

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.