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Thyroxine Binding Globulin

Item Value
Approval req'd? No
Available Stat? No
Test code TBG
Test group Thyroid tests
Performed by Quest
Sendout? Yes
Method Chemiluminescence
Container type Red top (Gold top NOT acceptable)
Amount to Collect 2 mL blood
Sample type Serum
Preferred volume 1 mL serum
Min. Volume 0.5 mL serum
UCSF Rejection Criteria Collected in Gold top.
Processing notes Freeze serum at -20°C. Order Quest # 30213P. For B&T patients order BTMOLT, LabCorp Test # 001735
Units µg/mL (mcg/mL)
Normal range
4-6 years 14.8-32.9 µg/mL
7-8 years 16.3-30.7 µg/mL
9-10 years 15.8-27.4 µg/mL
11 years 15.5-27.4 µg/mL
12 years 14.8-26.2 µg/mL
13 years 13.8-25.2 µg/mL
14 years 12.2-25.2 µg/mL
15 years 10.8-23.8 µg/mL
16 years 10.0-23.8 µg/mL
17 years 8.5-23.1 µg/mL

Tanner Stages Males Females
Stage I 13.5-28.4 µg/mL 14.2-28.5 µg/mL
Stage II 15.1-25.9 µg/mL 15.0-23.1 µg/mL
Stage III 14.0-26.3 µg/mL 13.7-23.0 µg/mL
Stage IV 13.2-25.0 µg/mL 12.0-22.8 µg/mL
Stage V 12.2-23.7 µg/mL 9.1-22.8 µg/mL

≥ 18 year old females 13.5-30.9 µg/mL
≥ 18 year old males 12.7-25.1 µg/mL

To convert to nmol/L, multiply the result by 18.5.

Synonyms TBG; T4 binding globulin
Stability Room temperature 1 week, refrigerated 1 week, frozen at -20C 1 month.
Turn around times Test performed Wednesday, Friday & Sunday. Turnaround time: 1-4 days.
Additional information TBG binds T4 and T3 (T4 more tightly than T3), and carries 70% of the thyroid hormone in the blood. It is indirectly estimated with Thyroid Uptake. Direct measurement is useful only for rare conditions such as congenital deficiency or excess of TBG
CPT coding 84442-90
LOINC code 3021-3
Last Updated 6/21/2016 12:22:02
Entry Number 922
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