Thyroxine-Binding Globulin (TBG), Serum
Additional Codes
LAB128
Performing Laboratory
 Mayo Clinic Laboratories in Rochester
Specimen Type
SerumSpecimen Required
Patient Preparation: For 12 hours before specimen collection, patient should not take multivitamins or dietary supplements (eg, hair, skin, and nail supplements) containing biotin (vitamin B7).
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL serum
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
Serum: 0.35 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | 
|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | 
| Frozen | 30 days | 
Reference Values
Males: 12-26 mcg/mL
Females: 11-27 mcg/mL
For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Monday, Wednesday, Friday
CPT Code Information
84442
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value | 
|---|---|---|
| TBGI | Thyroxine Binding Globulin, S | 3021-3 | 
| Result ID | Test Result Name | Result LOINC Value | 
|---|---|---|
| TBGI | Thyroxine Binding Globulin, S | 3021-3 |