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Test Code SQ T4 T4 (Thyroxine), Total, (Veterinarian), Plasma

Important Note


Patients receiving therapy with high biotin doses (i.e. > 5 mg/day), could cause a +/- 10% change in their test results. It is recommended by Roche that samples should not be drawn until at least 8 hours following the last biotin administration.


This test is for veterinary clients only.



Performing Laboratory

Meriter Laboratories

Specimen Requirements

Specimen Type: Plasma

Container/Tube: Light-green top (lithium heparin gel)

Specimen Volume: 1 mL

Collection Instructions: Avoid hemolysis.

Forms: Meriter Laboratories Veterinary Requisition in Special Instructions

Specimen Transport Temperature

Refrigerated/Frozen OK

Reference Values

Cat: 2.1-5.3 mcg/dL

Day(s) Test Set Up

Monday through Sunday

Analytical Time


1 hour


4 hours

Test Classification and CPT Coding

Not applicable

Specimen Requirements Additional Information



Specimen Stability:Plasma is stable refrigerated (2° C-8° C) for 7 days or frozen (≤-20° C) for 30 days. Freeze only once.