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Free Thyroxine Index (FT4I)
METHODOLOGY
This is not a test per-se. It is a calculated ratio of two tests: Total T4 / THBR
PERFORMED
Tuesday & Friday
REPORTED
2 days
REMARKS
FT4-Index Components: Thyroxine (T4), Thyroid Hormone Binding Ratio (THBR)
REFERENCE RANGE
4.5 – 12.5 (no units)
CPT CODES
84436 (T4), 84479 (THBR)
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