T3 FREE

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Note: This test is sensitive to Biotin and result may be falsely elevated in patients taking high doses.

Test Code

T3F

Alias/See Also

Free T3

CPT Codes
84481

Preferred Specimen

1 Gold tube (gel separator)

Minimum Volume

0.6 mL

Other Acceptable Specimens

or 1 Green tube (Lithium Heparin)

Instructions

Centrifuge for complete separation of plasma or serum and red cells within 2 hours.

Transport Temperature

Refrigerate

Specimen Stability

2-8°C up to 7 days
15-30°C up to 8 hours
Frozen samples are stable

Methodology

Chemiluminescent immunoassay

Setup Schedule

M, T, W, Th, F, Sa, Sun

Report Available

Within 24 hours of receipt at the performing laboratory.

Reference Range

2.52 - 4.34 pg/ml

Clinical Significance

Utilized in the diagnosis of T3-hyperthyroidism or to monitor patients with known thyroid disorders. Usually ordered following an abnormal T4 or TSH. Includes only the unbound hormone and is unaffected by protein levels.

Performed By
Alverno Laboratories

Performing Laboratory
Alverno Central Lab
NCHB2 (Chemistry, Beckman DxI)

Last Updated: June 9, 2023

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.