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Test Code TSHC Thyroid Stimulating Hormone (TSH), Ultra Sensitive LAB129

Performing Laboratory

UnityPoint The Finley Hospital

Test Method

Chemiluminescent immunoassay (sandwich principle); Roche cobas Pro

Performance

Testing is performed Monday through Sunday.

Routine: Typically completed the same day after the specimen arrives at the laboratory.

STAT: Typically completed within 4 hours after the specimen arrives at the laboratory.

Specimen Requirement

  1. Lithium heparin plasma (Green) is the specimen of choice. 
  2. Serum (Red/Gold) and EDTA plasma (Purple) are also acceptable sample types.
  3. Gel tubes are acceptable. 
  4. It is recommended that the serum or plasma be separated from contact with cells within 2 hours from time of collection.
  5. TSH specimens are stable for 8 days at 20-25°C, 14 days at 2-8°C, and 24 months at -20°C.

Useful For

The determination of TSH serves as the initial test in thyroid diagnostics. Even very slight changes in the concentrations of the free thyroid hormones bring about much greater opposite changes in the TSH level. Accordingly, TSH is a very sensitive and specific parameter for assessing thyroid function and is particularly suitable for early detection or exclusion of disorders in the central regulating circuit between the hypothalamus, pituitary and thyroid.

Reference Values

0.270 – 4.20 μIU/mL

CPT Code Information

84443 Chemistry: Thyroid Stimulating
Hormone

NCD Frequency Limitations: Testing may be
covered up to two times a year in clinically stable patients; more
frequent testing may be reasonable and necessary for patients whose
thyroid therapy has been altered or in whom symptoms or signs of
hyper or hypothyroidism are noted.

LOINC Code Information

11580-8 Thyrotropin [Units/Volume] In Serum Or Plasma By
Detection Limit ≤ 0.005 mLU/L

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