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FTIN
FREE THYROXINE INDEX (FTI), SERUM

Test Code FTIN 
Test FREE THYROXINE INDEX (FTI), SERUM 
Methodology Electrochemiluminescence Immunoassay (ECLIA) 
Description Includes total T4 and T4 uptake

NOTE: This test, when ordered on Medicare patients, is subject to the National Coverage Determination (NCD) policy "Thyroid Testing". Please verify that the diagnosis code (ICD-9) you have chosen demonstrates medical necessity for the test as documented in the physician's patient record. The CMS web site or the NorDx Limited Coverage Documentation Guide are available to assist you with this verification. A properly executed Advance Beneficiary Notice (ABN) must be submitted with the specimen if medical necessity is not demonstrated by the ICD-9 code chosen. 

Specimen Draw blood in either a plain, red-top tube or serum gel tube. Spin down and send 1.0 mL (minimum volume: 0.5 mL) of serum refrigerated. 
Reference Values T4, TOTAL
Adult:
5.3 - 12.3 g/dL
Pediatric:
Ages: 1 - 3 yrs: 6.8 - 13.5 g/dL
Ages: 3 - 10 yrs: 5.5 - 12.8 g/dL

T4 (THYROXINE), UPTAKE
0.8 - 1.3 TBI

FREE THYROXINE INDEX
4.4 - 11.4 g/dL 

Analytic Time 1 Day 
Day(s) Test Set Up Monday through Friday 
CPT Code(s) 84436  Thyroxine, total
84479  T4 uptake