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HelpTest Code T4F Free T4 Free Thyroxine
Alias
T4 Free
FT4
Free Thyroxine
Collection Method
Venous Collection
Container
Light Green Lithium Heparin tube
Instructions/Special Handling
None
Preferred Specimen
Light Green (Lithium Heparin) Plasma
Acceptable Specimes
- Serum
- Gold SST tube
- Red tube
- Plasma
- Light Green lithium heparin
- Lavender EDTA
Units
ng/dL
Reference Ranges
| Age | Reference Range |
| 0 minutes - 4 days | 1.00 - 3.00 ng/dL |
| 4 days - 30 days | 0.80 - 2.20 ng/dL |
| >30 days | 0.90 - 1.70 ng/dL |
Critical Values
N/A
Reasons for Rejection
| Hemolysis | N/A |
| Icterus | N/A |
| Lipemia | N/A |
| Other | QNS, Contaminated, Improperly labeled, Improper specimen type |
Specimen Stability
| Ambient (15-25°C) | 1 day |
| Refrigerated (2-8°C) | 7 days |
| Frozen (-20°C) | 30 days |
Performing Site
Boone Health Laboratory
Performance Information
| Days/Times Performed | Daily 24/7 |
| Expected Turn around Time | Same day |
| Methodology/Method Description | Roche Cobas - Electrochemiluminescence immunoassay |
Panel Components
N/A