top of page
Thyroxine, Total T4 (Total T4)
Ordering Recommendation
Preferred test for initial screening and monitoring of thyroid function.
Methodology
Quantitative Electrochemiluminescent Immunoassay (ECLIA)
Performed
Mon-Sat
Reported
Within 24 hours
New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation:
Collect:
Serum separator tube or green (lithium heparin). Also acceptable: lavender
Specimen Preparation:
Separate serum or plasma from cells ASAP or within 2 hours of collection. Allow serum specimen to clot completely at room temperature.
Storage/Transport Temperature:
Refrigerated.
Unacceptable Conditions:
Grossly hemolyzed specimens.
Remarks:
Stability:
After separation from cells: Ambient: 4 days; Refrigerated: 8 days; Frozen: 1 year
Reference Interval
Components
Available Separately
Reference Interval
Thyroxine, Total T4
Cord Blood
6.60-17.50 ug/dL
0-3 days
5.37-22.40 ug/dL
4-30 days
5.24-23.20 ug/dL
1-23 months
5.37-16.00 ug/dL
2-6 years
5.26-14.80 ug/dL
7-11 years
5.70-14.10 ug/dL
12-19 years
4.74-14.60 ug/dL
20 years and older
4.50-11.70 ug/dL
Interpretive Data
Note
CPT Code
84436
Components
Component Test Code
Component Chart Name
LOINC
3005980
Thyroxine, Total T4
3026-2
Aliases
Syn-Thyroid
T4
T4 Serum
T4 Total Only
Tetraiodothyronine
Thyroid Hormone
Thyroxine (T4)
Total T4
bottom of page