T3 uptake-994

Test info

  
T3 uptake
  
994
  
LAB994
  
MSO
  
  • Thyroid function test for the diagnosis of hypothyroidism or hyperthyroidism, used with thyroxine (T4) or equivalent to provide free T4 index, FTI.
  • An indirect measure of binding protein, the T3 uptake reflects available binding sites (ie, reflects TBG).
  • T3 uptake is not a measurement of serum T3. It should never be used alone; rather, its usual application is use with thyroxine (T4).

Specimen

  

Biotin supplements may interfere with assay.

It is recommended that patients abstain from any biotin containing supplement for 12 - 24 hours prior to blood draw. Biotin is commonly found in hair, skin and nail supplements and multivitamins.

  
Serum
  
  
1.0 mL
  
0.7 mL
  

Immediatley following collection, mix sample by gently inverting 5 times

  
  1. Allow sample to clot for a minimum of 30 minutes
  2. Spin within two (2) hours of sample collection
  

Gold serum separator (SST) tube

  
Lithium heparin (Li hep) plasma
  
  

Lt green plasma separator (PST):

Immediately following collection, mix sample thoroughly by gentle inverting 8 - 10 times to prevent clotting

  

Red: 

  1. Allow sample to clot
  2. Spin
  3. Transfer serum to a Transfer vial/tube with cap - 12mL (LabCorp), labelled as serum, within two (2) hours of sample collection

Lt green plasma separator (PST): 

Spin within two (2) hours of sample collection

  

Transfer vial/tube with cap - 12mL (LabCorp)

or

Lt green plasma separator (PST)

  

Ambient (preferred) - 14 days

Refrigerated - 14 days

Frozen - 14 days

Freeze/thaw cycles: stable x3

 

Performance

  
LabCorp Burlington (001156): R-NX
  
Daily
  
1 - 3 days
  

Electrochemiluminescence Immunoassay (ECLIA)

Clinical and Interpretive info

  

An interpretive report will be provided

  
Biotin interference - see Patient preparation

Billing

  
84479
  
Yes
  

Tracking

  
05/20/2019
  
08/13/2021
  
08/24/2021