Lab Test : Free T4

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Alternate:Free thyroxine; FT4
Includes:Free T4
Phone:(937) 641-3428
SQ Code:FT4
Available:Mon - Fri, first shift only
Turnaround:24 hours
Volume:0.7 mL
Container:4 mL red top tube
Temperature:Transport to lab within 30 minutes.
Rejection:Samples held at room temperature for more than 8 hours.
Normal:1 day: 0.74-2.52 ng/dL
4 days: 0.74-2.10 ng/dL
1 month: 0.77-2.02 ng/dL
1 year: 0.89-1.80 ng/dL
Uses:Thyroid evaluation.
Limitations:The anticonvulsant drug phenytoin may interfere with the total and free T4 levels due to competition for TBG binding sites. FT4 values may be decreased in patients with non-thyroid conditions and in patients taking carbamazepine.
Method:Competitive chemiluminescence immunoassay

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