Product Details

This test requires a blood draw, so please ensure you can refer to a phlebotomist in the clients area before you order this test.

Under certain conditions, the conversion of T4 to T3 can be impaired, resulting in high levels of reverse t3 (rT3). The majority of rT3 found in the circulation is formed by peripheral deiodination (removal of an iodine atom) of T4 (thyroxine).  

A selenium deficiency, excess physical, mental and environmental stresses can all inhibit the deiodinating enzyme which is responsible for this conversion. This can be termed 'sick euthyroid' or 'low T3 syndrome'. 

Sample Requirement: 0.8ml serum
Analytes measured: Reverse T3

Practical

Specimen requirements:

Before:
Drugs that may interfere with test results include glucocorticoids (e.g., prednisone), dopamine, lithium,
interferon-alpha, phenobarbital, phenytoin, heparin, clofibrate, carbamazepine, and colestipol. If you have
questions, please contact your healthcare practitioner.  (Do NOT discontinue any medication without consulting your practitioner.)
• Patient must fast for 12 hours prior to blood draw. (Do not eat solid food and drink only water when necessary).
• Please schedule your blood draw for Monday – Wednesday to leave enough time for the sample to reach the
laboratory before the weekend.

After:
• Write patients full name, date of birth, time and date of collection on collection tube.
• Red/grey topped SST and red topped amber transfer tube:
i. Draw the red/grey topped SST fully – must be at least 0.5ml.
ii. Mix blood sample thoroughly by gently inverting the tube 3-5 times. DO NOT SHAKE.
iii. Centrifuge the red/grey topped SST at 1000g for 15 minutes. The serum must be free of
hemolytic or red blood cells. (Centrifuge not needed, if we (at Nordic Labs) have the speciemen within 24 hours of blood draw.)
iv. Pipette all the serum from the red/grey SST into the red topped amber transfer tube.
v. Cap transfer tube tightly and place into the plastic tube holder and seal.
vi. If unable to send immediately, store in a refrigerator to keep specimen stable. DO NOT FREEZE.