Thyroid hormone – binding ratio
(THBR)

Sample type :-

Serum

Uses :-

measures the “uptake” of T3 or T4 tracer by Thyroid Binding Globulin (TBG) in a given serum sample. This provides an indirect and reciprocal estimate of the available binding sites on TBG within the sample.

Precautions :-

Interfering factors :-

It is directly proportional to the fraction of FT4 , and inversely proportional to the TBG binding sites.
Pregnancy ,estrogen and birth control pills alter the concentration of the thyroxine-binding protein
Invalid if other proteins or immunoglobulins compete with TBG, including Familial Dysalbuminemic Hypertuhyroxinemia.
Concordance values of T4 and THBR tests suggest altered thyroid function.
Discordant variance suggests primary change in TBG in a euthyroid state (e.g., pregnancy)

Pre-analytical errors :-

1- Unlabeled or mislabeled specimen

2- Hemolysis or lipemic samples

The corrective action

Reject the sample and another one will be requested.

Post-analytical errors:-

1- write wrong name on the report or wrong results and send the report to the patient.

2- Send the report to the wrong patient.

The Corrective action

1 - make sure that all data of the patient are correct.

2 - you must communicate with the patient and apologize for this mistake and sent the right report.

Reference range :-

5.93–13.13 μg/dL.