MICHIGAN INNOVATIVE DIAGNOSTICS

Assesses active thyroid hormone status, especially in hyperthyroidism.

​

LIS TEST CODE: FT3

​

CPT CODE: 84481

​

ALIASES: FT3, Free T3

​

METHODOLOGY: Chemiluminescent Microparticle Immunoassay (CMIA)

​

SPECIMEN:

​

- Type: Serum

​

- Container: Gold Top (SST) Vacutainer

​

- Minimum Volume Required: 1 mL

​

- Storage/Handling: Allow 30 minutes for blood to clot, then centrifuge specimen at 3500 RPM for 10 minutes. Maintain specimen in the refrigerator or in the freezer until testing can be performed.

 

NOTE: If freezing is required to preserve stability, transfer serum into a separate plastic screw-cap transport container.

​

- Stability:     Room Temperature (20-25 °C): Not Accepted    

 

Refrigerated (2-8 °C): 6 days

​

                        Frozen (-20 °C or colder): 6 days; avoid multiple freeze/thaw cycles.

​

- Turnaround Time: 24 hours from receipt.

​

Special Instructions: N/A

​

REJECTION REASONS: QNS, Gross Hemolysis, Gross Lipemia, Contamination, Stability Violation, Expired Container, Incorrect Container

​

REFERENCE RANGES:

​

Males & Females (pg/mL)

​

1 - 13 years of age: 3.0 - 5.1

14 - 18 years of age: 3.3 - 5.3

>= 19 years of age: 2.0 - 4.4

​​​​​​​​​

​