TSH with Reflex to Free T4

Test Code

TSHF

Alias/See Also

Epic: LAB9560

CPT Codes
84443

Includes

If TSH is ≥4.95, T4 Free (T4FRE) will be added.

Preferred Specimen

Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL

Minimum Volume

0.5 mL
(Collect two full microtainers for infants <10 days old)

Other Acceptable Specimens

Specimen Type: Plasma
Collection Container: Green top (Lithium heparin)

Instructions

Centrifuge and separate cells after clot formation and within 4 hours of collection. Remove serum if testing will be delayed more than 24 hours.

Transport Container

Plastic vial

Specimen Stability

Room temperature: Unacceptable
Refrigerated (on gel): 24 hours
Refrigerated (off gel): 6 days
Frozen: 6 months

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Samples stored on gel >24 hours, unlabeled, mislabeled, wrong tube type, hemolyzed, QNS, exceeds specimen stability requirements.

Setup Schedule

Daily

Report Available

Same day

Reference Range

0.35 - 4.94 IU/mL

Performing Laboratory

Inova Laboratories

2832 Juniper Street

Fairfax, VA 22031

Last Updated: March 9, 2023
Last Review: N. Wolford, March 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.