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HelpTest Code T3 Total Triiodothyronine (Total T3)
Additional Codes
| Epic Ordering Code | LAB136 |
| NBS code | LBC13058 |
| Service code | 31903 |
Specimen Requirements
Submit the following:
| Container: |
| Yellow Top |
Processing Requirements
Allow specimen to clot for 30 mins and centrifuge within 2 hours
Specimen type: Serum
Volume: 0.5mL
Specimen Stability
| Specimen Type | Serum |
|---|---|
| Ambient | 24 hours |
| Refrigerate | 6 days |
| Frozen | 1 year |
Specimen Condition
| Gross Haemolysis | Alert/Reject |
|---|---|
| Icterus | OK |
| Lipaemia | OK |
| Others | Not applicable |
Methodology
Chemiluminescent Immunoassay
Days and Times Performed
24 hrs, TAT 1 day
Reference Interval
| Age | Male | Female |
|---|---|---|
| 4 days – < 1 yr | 1.30 – 3.60 nmol/L | |
| 1 – 11 yrs | 1.74 – 2.91 nmol/L | |
| 12 – 14 yrs | 1.50 – 2.71 nmol/L | |
| 15 – 16 yrs | 1.44 – 2.40 nmol/L | 1.42 – 2.18 nmol/L |
| 17 – 18 yrs | 1.38 – 2.58 nmol/L | 1.33 – 2.58 nmol/L |
| ≥ 19 yrs | 0.54 – 2.96 nmol/L | |
Testing Laboratory
National University Hospital
Clinical Chemistry, 67724346
Useful For
Diagnosis of triiodothyronine toxicosis.
Reflects tissue mono-deiodination of thyroxine.
Update
Last updated 28/07/2026
LOINC Code Information
83125-5
Alias
Triiodothyronine, Total T3
Thyroid Function Cascade