Total T4 (Blood)

Testing Laboratory

Department

Chemical Pathology

Delphic Registration Code (Alpha Code)

MSN

Test Code (Numeric Code)

9932

Synonyms

thyroxine, total, total thyroxine, tT4

Specimen Type

• Plasma
• Serum

Specimen Requirements

Tube/Container Type:

Preferred

• Lithium Heparin - Non-gel (Green Cap)
• Plain (Red Top)

Preferred Sample Volume (ml)

5

Clinical note: TSH is the preferred initial test for hypo/hyperthyroidism. Free T4 (fT4) is helpful for assessing an abnormal TSH. Total T4 is rarely useful and should be requested only under specialist advice.

Registration note: This is not the same test as Free T4. If only "T4" or "thyroxine" is requested, register for Free T4.

Reference Intervals
Refer to Canterbury Health Labs online Test Guide

Laboratory Notes
Minimum 1 mL serum or heparin plasma required. Separate and send frozen to CHL.
Ensure it is clear that TOTAL T4 (not Free T4) is requested

Contact Information