Thyroid Stimulating Hormone with Thyroxine Reflex

Included Tests

Thyroid Stimulating Hormone (TSH); Thyroxine (Free T4)

Clinical Significance

This is the preferred alternative to the traditional Thyroid Profile (T4, T3 Uptake, FTI).

Reference Range:

TSH: 0.25 - 4.50 uIU/mL

Free T4: 0.80 - 1.80 ng/dL

Test Comments:

A Free T4 will automatically be performed and charged when the TSH is < 0.25 or > 4.50.

It has been noticed that allopurinol may falsely elevate TSH level. Cotesting with Free T4 and correlation with clinical symptoms are recommended in evaluation of thyroid function in this subset of patients.

TSH -- This assay utilizes biotin technology. Patients taking vitamin supplements containing high doses of biotin (> 5 mg/day) may have falsely decreased test results generated.
T4FRE -- This assay utilizes biotin technology. Patients taking vitamin supplements containing high doses of biotin (> 5 mg/day) may have falsely increased test results generated.

Methodology:

• Electrochemiluminescence (ECLIA)

Clinical Significance

This is the preferred alternative to the traditional Thyroid Profile (T4, T3 Uptake, FTI).

Documentation

Any order of a Thyroid Profile will change to this test code (TSHR).

CDM

01487695

CPT Coding

84443 (Reflexes 84439)

Medical Necessity May Apply