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22926 Thyroxine, Total

Thyroxine, Total
Test Code: T-4
Synonyms/Keywords
​T4 - Thyroxine, Total​
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ Plasma/Serum​Lithium Heparin Plasma Separator Tube (PST)
Lithium Heparin Green Top (GTT), Serum Separator Tube (SST), ​Red Top Tube (RTT)​1.0 mL​0.5 mL​0.3 mL​
Collection Processing Instructions

​GTT/RTT- physically separate plasma or serum from contact with cells as soon as possible or before transport.

Specimen Stability Information
Specimen Type Temperature Time
​​Serum​ ​Ambient
8 hours​
Refrigerated​
 24 hours​
Frozen​ >24 hours​
Rejection Criteria
Gross Hemolysis
Marked Icterus
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ Less than 2 hours​
 Immunoenzymatic assay/ Beckman Coulter Unicel DXI
Test Information
Medicare patients must sign a waiver before specimen is collected since Medicare considers this a non-covered test.​
Reference Range Information
Performing Location Reference Range
Marshfield​ ​
​0 to < 4 years:
​5.9-13.1 ug/dL
​4 to < 14 years:
​5.4-10.1 ug/dL
​Female 14 to < 19 years:
​5.8-11 ug/dL
​Male 14 to < 19 years:
​5.3-9.2 ug/dL
​Adult (> 19 years): 
​6.1-12.2 ug/dL​

Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84436  ​ ​ ​ ​ ​
Synonyms/Keywords
​T4 - Thyroxine, Total​
Ordering Applications
Ordering Application Description
​Centricity ​T4-Thyroxine
​Cerner ​Thyroxine
​COM ​T4 - Thyroxine, Total
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Fasting Required Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)		 Pediatric Minimum Volume
(no repeat)
No​ Plasma/Serum​Lithium Heparin Plasma Separator Tube (PST)
Lithium Heparin Green Top (GTT), Serum Separator Tube (SST), ​Red Top Tube (RTT)​1.0 mL​0.5 mL​0.3 mL​
Collection Processing

​GTT/RTT- physically separate plasma or serum from contact with cells as soon as possible or before transport.

Specimen Stability Information
Specimen Type Temperature Time
​​Serum​ ​Ambient
8 hours​
Refrigerated​
 24 hours​
Frozen​ >24 hours​
Rejection Criteria
Gross Hemolysis
Marked Icterus
Reference Range Information
Performing Location Reference Range
Marshfield​ ​
​0 to < 4 years:
​5.9-13.1 ug/dL
​4 to < 14 years:
​5.4-10.1 ug/dL
​Female 14 to < 19 years:
​5.8-11 ug/dL
​Male 14 to < 19 years:
​5.3-9.2 ug/dL
​Adult (> 19 years): 
​6.1-12.2 ug/dL​

For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
Marshfield​ Monday through Sunday​ Less than 2 hours​
 Immunoenzymatic assay/ Beckman Coulter Unicel DXI
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)		 Quantity Description Comments
84436  ​ ​ ​ ​ ​
For most current information refer to the Marshfield Laboratory online reference manual.