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HelpTest Code LAB128 Thyroxine-Binding Globulin (TBG), Serum
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Thyroxine Binding Globulin, SSpecimen Type
SerumSpecimen Required
Patient Preparation: For 12 hours before specimen collection, do not take multivitamins or dietary supplements containing biotin (vitamin B7), which is commonly found in hair, skin, and nail supplements and multivitamins.
Collection Container/Tube:
Preferred: Red top
Acceptable: Serum gel
Submission Container/Tube: Plastic vial
Specimen Volume: 0.5 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 30 days |
Specimen Minimum Volume
0.35 mL
Day(s) Performed
Monday, Wednesday, Friday
Specimen Retention Time
2 weeksReport Available
1 to 3 daysReference 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
Useful For
Cases in which total thyroid hormone levels do not correlate with the thyrometabolic status, most commonly with pregnancy or the use of contraceptive steroids
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 |