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Test Code 1249 Thyroid-Stimulating Hormone-Sensitive (s-TSH) with Reflex T4 (Thyroxine), Free and T3 (Triiodothyronine), Free, Plasma or Serum



Testing Algorithm:
Includes sensitive TSH with reflex testing to T4, free if the TSH is abnormal, and further reflexing to T3, free, if T4, free is normal or decreased. Reflexed tests will include an additional charge.

General Information:
Useful for evaluating and monitoring thyroid function.

Performing Laboratory

CoxHealth Laboratories-Chemistry

Specimen Requirements

Submit only 1 of the following specimens:


Container/Tube: Green-top (heparin) tube(s)

Specimen Volume: 3 mL (minimum volume: 1 mL) of plasma

Collection Instructions:

Note: 1. Indicate plasma.

2. Label specimen appropriately (plasma).



Container/Tube: Serum gel tube(s)

Specimen Volume: 3 mL (minimum volume: 1 mL) of serum

Collection Instructions:

Note: 1. Indicate serum.

2. Label specimen appropriately (serum).

Specimen Transport Temperature


Reference Values


1-30 days: 0.520-16.000 µIU/mL
31 days-5 years: 0.460-8.100 µIU/mL
6 years-18 years: 0.360-6.000 µIU/mL
Adults: 0.358-3.740 µIU/mL

Day(s) Test Set Up

Monday through Sunday

Test Classification and CPT Coding


84439-T4, free (if applicable)

84481-T3, free (if applicable)