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HelpTest Code T4BPE Thyroxine-Binding Protein Electrophoresis, Serum
Useful For
Explaining unusual thyroxine (T4), free T4, and thyroxine-binding globulin test results that do not correlate with the patient's clinical presentation
Detecting the presence of aberrant thyroxine-binding proteins, such as abnormal forms of albumin and prealbumin
Detecting selective deficiency of one of the thyroxine-binding proteins
Detecting antibodies to T4
An adjunct to the diagnosis of patients with high T4 concentration due to peripheral hormone resistance by ruling out thyroxine-binding abnormalities
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TBPE | Thyroxine-Binding Protein Electro | No | Yes |
| T4 | T4 (Thyroxine), Total Only, S | Yes | Yes |
Method Name
TBPE: Electrophoresis
T4: Electrochemiluminescence Immunoassay (ECLIA)
Reporting Name
Thyroxine-Binding Protein ElectroSpecimen Type
SerumOrdering Guidance
This assay measures thyroxine binding to various proteins.
For analysis of thyroxine-binding globulin, see TBGI / Thyroxine-Binding Globulin (TBG), Serum.
For immunologic assay of prealbumin, see PALB / Prealbumin, Serum.
This test should not be requested in patients who have recently received radioisotopes, therapeutically or diagnostically, because of potential assay interference. A recommended time period before collection cannot be made because it will depend on the isotope administered, the dose given, and the clearance rate in the individual patient.
The total thyroxine (T4) test should not be used in patients receiving treatment with lipid-lowering agents containing dextrothyroxine unless therapy is discontinued for 4 to 6 weeks to allow the T4 physiological state to become re-established prior to testing.
Specimen 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: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1.6 mL
Collection Instructions: Centrifuge and aliquot serum into a plastic vial.
Specimen Minimum Volume
0.8 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 7 days | |
| Frozen | 30 days | ||
| Ambient | 24 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | Reject |
| Gross icterus | Reject |
Reference Values
THYROXINE-BINDING PROTEIN ELECTROPHORESIS:
10.3-24.9 mcg T4/dL bound to thyroxine-binding globulin
11.5-34.1 mcg T4/dL bound to albumin
48.8-70.4 mcg T4/dL bound to prealbumin
T4 (THYROXINE), TOTAL ONLY:
Pediatric:
0-5 days: 5.0-18.5 mcg/dL
6 days-2 months: 5.4-17.0 mcg/dL
3-11 months: 5.7-16.0 mcg/dL
1-5 years: 6.0-14.7 mcg/dL
6-10 years: 6.0-13.8 mcg/dL
11-19 years: 5.9-13.2 mcg/dL
Adult (≥20 years): 4.5-11.7 mcg/dL
For SI unit Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html
Day(s) Performed
Fourth Friday of the month
Report Available
29 to 35 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
84436
82664
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| T4BPE | Thyroxine-Binding Protein Electro | 48073-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 2860 | TBG | 14016-0 |
| 2861 | Albumin | 11062-7 |
| T4 | T4 (Thyroxine), Total Only, S | 83119-8 |
| 2862 | Pre-Albumin | 14014-5 |
| 2863 | Abnormal Binding Protein | 48767-8 |
| 3345 | Comment | 50681-6 |