Thyroxine- Binding Globulin
(TBG)

Sample type:-

Serum

Uses:-

1. measures the level of a protein that moves thyroid hormone throughout your body.

2. Diagnosis of genetic or idiopathic excess TBG

3. Sometimes used to detect recurrent or metastatic differentiated thyroid carcinoma, especially follicular type and where the patient has had an increased level due to carcinoma.

Precautions:-

• Many different medications and drugs can affect the TBG levels , So the doctor may then advise the patient to stop taking any of these medications temporarily before your TBG test.

• transfer separated serum to a plastic transport tube.

Interfering factors:-

1. Elevated TBG levels are associated with influences such as pregnancy, genetic predisposition, oral contraceptives, and estrogen therapy.

2. Decreased binding of T3 and T4 due to drugs (salicylates, phenytoin, Orinase, Diabinese, penicillin, heparin, barbital)

3. Hemolysis specimen.

4. A change in thyroxine-binding globulin (TBG) concentration may be of hereditary, pathophysiologic, or pharmacologic origin.

Pre – analytical errors:-

1. Gross hemolysis specimen.

2. Unlabeled or mislabeled specimen

The Corrective action

1. Reject the sample and another one is obtained.

2. Reject the sample and another sample will requested and make sure that all data of the patient is correct.

Post – analytical errors:-

1. Write wrong name on the report.

2. Send wrong results to the patient.

The Corrective action

1. make sure that the name and all data are right

2. Communicate to the patient and apologize for this mistake and sent the right report to him.

Reference range:-

Males: 12-26 mcg/mL

Females: 11-27 mcg/mL