test directorySearch Results
Click here to search again.
Test Name:
T3, Total
- SBMF No:
30012 - Performance Lab Name:
Automated Lab - Test Mnemonic:
T3 TOTAL - ABN:
Not required - CPT Code:
84480 - LOINC Code:
3053-6 - Also Known As:
Triiodothyronine, Total
Total T3 - Also See:
30016 T3, Free
30213 T4, Total
30113 T4, Free - Spec Type:
Serum - Spec Container:
Gold top (SST) or red top (serum) tube - Alt Spec Type:
Plasma - Alt Spec Container:
Green top (lithium heparin) tube - Pref Vol:
1.6 mL - Min Vol:
0.8 mL - Fasting:
No - Spec Collect:
Routine venipuncture - Spec Process:
Serum sample tubes, clot 30 minutes
Promptly centrifuge 15 minutes
Immediately transfer serum or plasma to separate plastic tube
Properly centrifuged gel barrier tube sample does not require transfer of serum to separate tube - Spec Store Transport:
Refrigerated - Spec Stability:
1 week refrigerated (2-8°C)
1 month frozen (-20°C) – Do not use frost-free units that undergo repeated freeze/thaw cycles - Spec Remarks:
Preferred specimen is primary serum sample contained in properly centrifuged gel barrier tube (not necessary to transfer serum to separate tube) - Methodology:
Electrochemiluminescent Immunoassay (ECLIA) - Use:
Utilized in the diagnosis of T3-hyperthyroidism, the detection of early stages of hyperthyroidism and for indicating a diagnosis of thyrotoxicosis factitia - Clinical Significance:
Triiodothyronine (T3) is the hormone principally responsible for the development of the effects of the thyroid hormones on the various target organs. T3 (3, 5, 3’-triiodothyronine) is mainly formed extrathyroidally, particularly in the liver, by enzymatic 5’-deiodination of T4. Accordingly, the T3 concentration in serum is more a reflection of the functional state of the peripheral tissue than the secretory performance of the thyroid gland. A reduction in the conversion of T4 to T3 results in a fall in the T3 concentration. It occurs under the influence of medicaments such as propanolol, glucocorticoids or amiodarone and in severe non-thyroidal illness (NTI), and is referred to as the “low T3 syndrome.” As with T4, over 99% of T3 is bound to transport proteins. However, the affinity of T3 to them is around 10-fold lower.
The determination of T3 is utilized in the diagnosis of T3-hyperthyroidism, the detection of early stages of hyperthyroidism and for indicating a diagnosis of thyrotoxicosis factitia. - Reference Range:
80-200 ng/dL - Additional Test Info:
Interferences:Therapy with amiodarone can lead to depressed T3 values. Phenytoin, phenylbutazone and salicylates cause release of T3 from the binding proteins, thus leading to a reduction in the total T3 hormone level at normal fT3 levels. Auto-antibodies to thyroid hormones can interfere with the test.
Abnormal concentrations of binding proteins (TBG, albumin) can lead to total T3 values outside the normal range being found despite a euthyroid metabolic state (e.g. in NTI-patients, pregnancy, use of oral contraceptives). In patients with very serious general diseases, differences to Enzymum-Test® T3 results may occasionally occur. In such cases an fT3 or fT4 determination is indicated. - Day Run:
Sun-Sat (daily) - Time Run:
As received - Time Reported:
4 hours - Test Type:
HORMONE
