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Test Code T3 T3

Additional Codes

Epic: LAB136

Specimen Required

Collection Container/Tube: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 3.0 mL
Collection 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.

Specimen Minimum Volume

0.5 mL

Specimen Stability

Room Temperature: Unacceptable
Refrigerated (on gel): 24 hours
Refrigerated (off gel): 6 days
Frozen: >6 days

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.

Reference Range

0.58 - 1.59 ng/mL

Rejection Due To

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

Day(s) and Time(s) Performed

Daily

Report Available

Same day

Method Name

Chemiluminescent microparticle immunoassay (CMIA)

LOINC

3053-6

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