Test Code T4 T4, LAB126
Methodology
Homogeneous Enzyme Immunoassay (EIA)
Performing Laboratory
St. Luke's Hospital Cedar Rapids
Specimen Requirements
Container/Tube:
Prefered: Green-top (lithium heparin) tube
Acceptable: Gold-top serum gel tube or plain, red-top tube
Specimen Volume: 0.1 mL of plasma or serum
Stability: Separated samples stored at 2 – 8°C and analyzed within 30 days
Collection Instructions:
Note: 1. Anti-thyroxine antibodies will interfere with this assay.
2. Human anti-mouse antibodies or other heterophile antibodies may be present in patient specimens. This assay has been specially formulated to minimize the effects of these antibodies, however results from patients known to have these antibodies should be carefully evaluated.
3. Venipuncture should occur prior to sulfasalazine and/or sulfapyridine administration due to the potential for falsely depressed results.
Reference Values
Age Group |
Total T4 |
Neonates 0 - 7 days |
8.9 – 31.0 mcg/dL |
Neonates 8 - 29 days |
13.9 – 41.5 mcg/dL |
Infants 1 – 23 months |
7.4 – 14.3 mcg/dL |
Children 2 years – 12 years |
6.8 – 12.5 mcg/dL |
Adolescents 13 years – 20 years |
6.0 – 11.6 mcg/dL |
Adults ≥21 years |
4.7 – 13.3 mcg/dL |
Day(s) Test Set Up
Monday through Saturday
Test Classification and CPT Coding
84436
Useful For
Thyroid funtion
Report Available
STAT within 1 hour upon receipt
ROUTINE within 2 hours upon receipt