Search
thyroxine [T4] (total) in serum
Reference interval:
- Adult male: 4.6-10.5 ug/dL
- Adult female: 5.5-11.0 ug/dL
- 5.0-10.7 ug/dL, age > 60 years
Increases:
1) hyperthyroidism
2) euthyroid hyperthyroxinemia
a) increased thyroid-binding globulin (TBG) caused by:
- estrogens
- pregnancy
- hepatitis
- porphyria
- biliary cirrhosis
b) familial dysalbuminemia
c) increased T4 binding to transthyretin
d) anti T4 antibodies
Decreases:
1) hypothyroidism
2) euthyroid hypothyroxinemia: (decreased thyroid-binding globulin)
- androgens
- glucocorticoids
- nephrotic syndrome
- systemic illness
Method:
- immunoassay
Specimen:
- serum, refrigerate immediately, stable for 7 days at room temp, but storage at 4 C preferred.
Related
free thyroxine index (fT4I)
thyroxine (T4)
thyroxine [T4] (free) in serum
Specific
thyroxine [T4] (albumin-bound) in serum
thyroxine [T4] (prealbumin-bound) in serum
thyroxine [T4] (thyroxine-binding globulin-bound) in serum
General
thyroxine [T4] (total) in body fluid
thyroid function test
References
- Clinical Guide to Laboratory Tests, 3rd edition, NW Tietz
ed, WB Saunders, Philadelphia, 1995
- Medical Knowledge Self Assessment Program (MKSAP) 11, American
College of Physicians, Philadelphia 1998
- Thyroxine
Laboratory Test Directory ARUP: 70140
- Panel of 3 tests
Laboratory Test Directory ARUP: 70141
Component-of
thyroid panel
thyroxine (T4)/thyroxine-binding globulin (TBG) in serum/plasma
triiodothyronine (T3)/thyroxine (T4) in serum/plasma