T3 Reverse, LC/MS/MS
Test Summary
3,3',5'-Triiodothyronine (reverse T3, rT3) is, along with 3,3,5'-Triiodothyronine (T3) a deiodinated metabolite of thyroxine (T4), the major secretory product of the thyroid gland and is secreted into the bloodstream. Unlike T3, however, rT3 is thought to be metabolically inert.
The process of 5'-monodeiodination that converts T4 to T3, and rT3 to diiodothyronine (DTT) is inhibited in a wide variety of conditions, collectively referred to as nonthyroidal illnesses (NTI) or the 'euthyroid sick' state. These conditions include fasting, malnutrition, poorly controlled diabetes mellitus, trauma, surgery, and systemic illness. Consequently, in patients with NTI the serum T3 level typically decreases, and the rT3 often, but not always, increases.
Aliases
- Reverse T3
- RT3
Specimen Collection
Special Instructions
Preferred Specimen
Minimum Volume
Instructions
Serum: Allow blood to clot at room temperature for 30 minutes. Centrifuge to separate serum from the cells within 24 hours of collection and immediately pour serum into a plastic transport tube.
Plasma: Centrifuge to separate plasma from the cells within 24 hours of collection and immediately pour plasma into a plastic transport tube.
Patient Preparation
Storage
Transport Temperature
Specimen Stability
- Room temperature: 7 days
- Refrigerated: 7 days
- Frozen: 30 days
Limitations
Other Acceptable Specimens
Unacceptable Specimens
Order Code
EPIC (Premier) Code
Includes
CPT Code
- 84482
Billing Code
- 700000
CPT Statement
Methodology
FDA Status
Physician Attestation of Informed Consent
Testing Laboratory
14225 Newbrook Drive
Chantilly VA, 20153
Reference Range
Setup Schedule / Expected Turnaround Time
Specimen Collection
Special Instructions
Preferred Specimen
Minimum Volume
Instructions
Serum: Allow blood to clot at room temperature for 30 minutes. Centrifuge to separate serum from the cells within 24 hours of collection and immediately pour serum into a plastic transport tube.
Plasma: Centrifuge to separate plasma from the cells within 24 hours of collection and immediately pour plasma into a plastic transport tube.
Patient Preparation
Storage
Transport Temperature
Specimen Stability
- Room temperature: 7 days
- Refrigerated: 7 days
- Frozen: 30 days