A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
Free Thyroxine Index (T7)
MessageFor Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.
Test Code
FTI
Alias/See Also
FTI,
T7,
Free Thyroxine Index
T7,
Free Thyroxine Index
CPT Codes
84479
Includes
Thyroxine, Total;
T3 Uptake
T3 Uptake
Preferred Specimen
SERUM
Minimum Volume
1 mL
Other Acceptable Specimens
Plasma from Lithium Heparin (Light Green Top) tube
Instructions
Barrier tubes (serum separator tubes or plasma separator tubes) are preferred. If non-barrier tubes are utilized, the serum/plasma must be removed immediately after centrifuging and placed in a screw-cap transfer tube.
Collection notes: Avoid hemolysis. Invert tubes at least 8 times. Allow to clot in an upright position for 30 minutes. Within 2 hours, centrifuge tubes 10 minutes. Keep tightly stoppered.
Do NOT re-centrifuge tubes. Do NOT freeze the primary collection tube.
Collection notes: Avoid hemolysis. Invert tubes at least 8 times. Allow to clot in an upright position for 30 minutes. Within 2 hours, centrifuge tubes 10 minutes. Keep tightly stoppered.
Do NOT re-centrifuge tubes. Do NOT freeze the primary collection tube.
Transport Container
Original tube preferred, may be sent in a screw-top transfer tube.
Transport Temperature
Room Temperature or Refrigerated
Specimen Stability
Room Temperature: 4 Days
Refrigerated: 8 Days
Frozen: 12 months
Refrigerated: 8 Days
Frozen: 12 months
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis, Lipemia, incorrect specimen type, insufficient sample volume, improper storage conditions, exceeds specimen stability guidelines, contaminated sample.
Methodology
Calculation.
Thyroid Index (T7), also called Free Thyroxine Index (FTI), is a calculation requiring both a total T4 and a T3-Uptake. T7= (T4 x T3-Uptake)/100
Setup Schedule
24/7
AU
AU
Report Available
Daily
Performing Laboratory
CompuNet Clinical Laboratories, LLC
2308 Sandridge Drive
Moraine, Ohio 45439
Last Updated: January 18, 2024