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| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
T4 (Thyroxine), Total
Test Code867
CPT Codes
84436
Preferred Specimen
1 mL serum
Minimum Volume
0.5 mL
Other Acceptable Specimens
Plasma collected in a sodium or lithium (green-top) tube
Transport Container
Plastic screw-cap vial
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 days
Refrigerated: 7 days
Frozen: 28 days
Methodology
Immunoassay (IA)
Setup Schedule
Set up: Daily; Report available: Next day
Limitations
Nonthyroidal chronic diseases, nicotinic acid and nutrition may decrease results. Thyrotoxicosis may not always cause abnormal results. Binding protein variations may cause variations in results. Increases may be associated with pregnancy or oral contraceptive use.
Reference Range
T4 (Thyroxine), Total
| Male (mcg/dL) | Female (mcg/dL) | ||||
| <1 Month | 4.5-17.2 | 4.5-17.2 | |||
| 1-23 Months | 5.9-13.9 | 5.9-13.9 | |||
| 2-12 Years | 5.7-11.6 | 5.7-11.6 | |||
| 13-20 Years | 5.1-10.3 | 5.3-11.7 | |||
| >20 Years | 4.9-10.5 | 5.1-11.9 |
| Free T4 Index (T7) | 1.4-3.8 |
Clinical Significance
For diagnosis of hypothyroidism and hyperthyroidism.
