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T3, Total

Item Value
Test Update Information Effective March 19, 2013, Total T3 testing is being performed on the Abbott Architect i2000 immunoassay analyzer. Note new reference ranges and the change in reporting units from ng/dL with the previous T3 assay (Axsym assay) to the new units in nmol/L.

Conversion formula: (Concentration in ng/dL) x (.01536) = concentration in nmol/L.
Approval req'd? No
Available Stat? No
Test code T3
Test group Thyroid tests
Performed by China Basin Chemistry
In House Availability Monday - Saturday (day shift)
Method Chemiluminescent Microparticle Immunoassay (Abbott Architect i2000)
Container type Gold top or Light Green top
Amount to Collect 1 mL blood
Sample type Serum or plasma
Preferred volume 0.5 mL serum or plasma
Min. Volume 0.25 mL serum or plasma
Processing notes Refrigerate.
Units nmol/L
Normal range
Age Male Female
0-12 months 0.9-3.1 nmol/L 1.6-3.5 nmol/L

Age Male & Female
1-5 years 1.6-3.1 nmol/L
6-10 years 1.6-2.8 nmol/L
11-14 years 1.0-2.9 nmol/L
15-18 years 1.1-2.7 nmol/L
>18 years 0.9-2.4 nmol/L

Adult reference ranges adopted from manufacturer reference range studies (95% CI) and verified in-house using blood donor samples (N=124) (excluding autologous donors) on no medications and negative for anti-Tg and TPO antibodies.

Pediatric reference ranges adopted from Clinical Biochemistry 42 (2009) 885-891. Canadian Laboratory Initiative on Pediatric Reference Interval Database (CALIPER).
Synonyms Triiodothyronine
Turn around times 0 to 2 days
Additional information The total T3 level may be elevated in the < 5% of hyperthyroid patients in whom the FT4 level is normal (T3 toxicosis). Measurement of T3 is of no value in the diagnosis of hypothyroidism. Total T3 can be affected by changes in thyroid binding protein levels. Measurements of Free T3 better reflect biologically active hormone levels than measurements of total T3.
CPT coding 84480
LOINC code 3053-6
Last Updated 6/21/2016 14:05:14
Entry Number 914
Lab Procedure Link Click here for Procedure
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