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T3

Test Code
T3


Alias/See Also
Epic: LAB136

T3 Total, Serum
Triiodothyronine
 


Preferred Specimen

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




Minimum Volume

0.5 mL




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 days




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

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




Methodology

Chemiluminescent microparticle immunoassay (CMIA)



Setup Schedule

Daily




Report Available

Same day




Limitations

For diagnostic purposes, results should be used in conjunction with other data: symptoms, results of other thyroid tests, clinical impressions, etc.
The ARCHITECT Total T3 assay is designed to have a mean potential interference from hemoglobin, bilirubin, triglycerides, and protein of <10% at : 
Hemoglobin ≤ 500 mg/dL
Bilirubin ≤20 mg/dL
Triglycerides ≤ 2000 mg/dL
Protein ≤ 12 g/dL 
 




Reference Range
0.58 - 1.59 ng/mL


Clinical Significance
Triiodothyronine (T3) is a thyroid hormone with a half-life in serum of 1.5 days.  T3 circulates in the blood as an equilibrium mixture of free and protein bound hormone.  It has become apparent in recent years that T3 plays an important role in the maintenance of the euthyroid state.  Serum T3 can be a component of thyroid screening panels in diagnosing certain disorders of thyroid function, particularly hyperthyroidism and conditions caused by iodine deficiency.  Slightly elevated T3 may occur in pregnancy and during estrogen therapy, while depressed levels may occur during severe illness, malnutrition, in renal failure and during therapy with anti-thyroid drugs.


Performing Laboratory

Inova Laboratories

2832 Juniper Street

Fairfax, VA 22031




Last Updated: March 8, 2023
Last Review: N. Wolford, March 8, 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.