Free Thyroxine Index (T7)
Test Summary
Thyroid Index (T7), also called Free Thyroxine Index (FTI), is a calculation requiring both a total T4 and a T3-Uptake.
Aliases
- FTI, T7, Free Thyroxine Index
Specimen Collection
Special Instructions
N/A
Preferred Specimen
1 mL serum
Minimum Volume
1 mL
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.
Patient Preparation
N/A
Storage
Original tube preferred, may be sent in a screw-top transfer tube.
Transport Temperature
Room Temperature or Refrigerated
Specimen Stability
- Room Temperature: 5 Days
- Refrigerated: 7 Days
- Frozen: 30 days
Limitations
N/A
Other Acceptable Specimens
Plasma from Lithium Heparin (Light Green Top) tube
Unacceptable Specimens
Hemolysis, Lipemia, incorrect specimen type, insufficient sample volume, improper storage conditions, exceeds specimen stability guidelines, contaminated sample.
Order Code
FTI
EPIC (Premier) Code
LAB2132
Includes
Thyroxine, Total;
T3 Uptake
T3 Uptake
CPT Code
- 84479
Billing Code
- 300399
CPT Statement
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
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
FDA Status
FDA Approved
Physician Attestation of Informed Consent
N/A
Testing Laboratory
CompuNet Clinical Laboratories, LLC
2308 Sandridge Drive
Moraine OH, 45439
2308 Sandridge Drive
Moraine OH, 45439
Department
Chemistry
Reference Range
See Report
Setup Schedule / Expected Turnaround Time
24/7; Report available: Daily
Specimen Collection
Special Instructions
N/A
Preferred Specimen
1 mL serum
Minimum Volume
1 mL
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.
Patient Preparation
N/A
Storage
Original tube preferred, may be sent in a screw-top transfer tube.
Transport Temperature
Room Temperature or Refrigerated
Specimen Stability
- Room Temperature: 5 Days
- Refrigerated: 7 Days
- Frozen: 30 days
Limitations
N/A
Other Acceptable Specimens
Plasma from Lithium Heparin (Light Green Top) tube
Unacceptable Specimens
Hemolysis, Lipemia, incorrect specimen type, insufficient sample volume, improper storage conditions, exceeds specimen stability guidelines, contaminated sample.
Result Information
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
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
Testing Laboratory
N/A
Reference Range
See Report
Setup Schedule / Expected Turnaround Time
24/7; Report available: Daily