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Test Code


CTP Code(s)

Clinical Significance

Preliminary test used to diagnose thyroid disorders. TSH is generally high in primary hypothyroidism and low TSH occurs in hyperthyroidism. Evaluation of hormone replacement therapy in hypothyroid patients receiving various thyroid hormone preparations: Low values are found in states of excessive thyroid replacement. Normal result on a sensitive TSH assay is acceptable evidence of adequate thyroid replacement. High values are found in cases where a higher dosage of thyroid replacement is needed. The third-generation TSH assay can be considered a test for thyroid disease. A result within the accepted reference interval provides strong evidence for euthyroidism. Also, TSH is not elevated in secondary hypothyroidism.

Test Resources

None found for this test Please visit our CLINICAL EDUCATION CENTER to stay informed on any future publications, webinars, or other education opportunities.

Test Details


Thyroid-stimulating Hormone (TSH)

Patient Preparation

This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.


Immunoassay (IA)

Reference Range(s)
    0 to 6 d0.700−15.200
    7 d to 3 m 0.720−11.000
    3 m 1 d to 12 m0.730−8.350
    1 to 5 y0.700−5.970
    6 to 10 y0.600−4.840
    >10 y0.450−4.500
Alternative Name(s)

Third-generation TSH, Thyrotropin

LOINC codes


Preferred Specimen(s)


Alternative Specimen(s)

Red-top tube or gel-barrier tube

Minimum Volume

0.3 mL (Note: This volume does not allow for repeat testing.)

Collection Instructions

If a red-top tube is used, transfer separated serum to a plastic transport tube.

Transport Container

Red-top tube, SST, Serum Aliquot

Transport Temperature

Room Temperature

Specimen Stability

Room temperature 14 days Refrigerated 14 days Frozen 14 days Freeze/thaw cycles Stable x3

Reject Criteria

Citrate plasma specimen; improper labeling

Setup Schedule


Reference ranges serve as a general guideline. The laboratory report will contain the most current interpretaion.

AMA provides guidance for the refernced CPT codes. We provided them for informational purposes only. CPT coding is the sole responsibility of the billing party. If you have coding questions please refer to the payer being billed.

This material contains content from LOINC® ( The LOINC Table, LOINC Table Core are copyright © 1995-2019, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee and is available at no cost under the license at

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