Triiodothyronine (T3), Free, Dialysis and LC/MS-MS (Endocrine Sciences)

Casandra

Casandra Test Code LC94496Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 503600CPT Code 84481

Triiodothyronine (T3), Free, Dialysis and LC/MS-MS (Endocrine Sciences)

Also known as: Free T3, Free Triiodothyronine (T3), FT3

Clinical Use

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Use

Triiodothyronine (T3), Free, Dialysis and LC/MS-MS test is primarily used to provide a direct measurement of free tri-iodothyronine, a thyroid hormone, in the blood. This test is employed to assess thyroid function in various clinical scenarios, especially when normal protein binding may be altered, enhancing accuracy over automated methods. Conditions where this test is preferred include congenital thyroxine-binding protein deficiency, pregnancy, oral contraceptive or hormone therapy users, and those with critical illnesses. It helps in diagnosing hyperthyroidism, assessing thyroid function in patients with thyroid dysfunction, and monitoring patients on thyroid hormone replacement therapy.

Special Instructions

Serum or plasma should be separated from cells within 45 minutes of venipuncture. Ensure the serum/plasma is sent in a plastic transfer tube. Proper separation and handling of the specimen are crucial to avoid degradation or incorrect results.

Limitations

This test may not be suitable for patients whose samples cannot be prepared and analyzed quickly or handled correctly due to logistical issues. Furthermore, it may require additional confirmatory testing depending on clinical context. Results can be influenced by non-thyroidal illnesses due to altered protein levels or increased protein binding produced by various medications or clinical conditions.

Test Details