bih.button.backtotop.text
BROWSE BY TEST NAME
%
1
2
3
5
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Clear
 
Test Code:
FT3

Order Name:
Free T3

 
Useful For:
Determination of free triiodothyronine (Free T3) in human serum.

Used as an aid in the assessment of thyroid status.
 
Methodology:
Chemiluminescent Microparticle Immuno Assay (CMIA)
 
AliasesName:
Free Triiodothyronine
FT3
Triiodothyronine, Free
 
 
 
Test Code:
FT3

Order Name:
Free T3

 
Collection Specimen Or Container:
Blood/ Plain Blood (Red Top) 6 mL, 1 tube
 
Specimen Testing Type:
Serum, minimum volume 1 mL
 
Sub Mission Container:
Plastic vial
 
Rejection Criteria:
Hemolysis: 4+ reject
 
Specimen Stabillity:
Specimen Type Temperature Time
Serum (keep in original tube) Refrigerated, 2oC to 8oC 8 hours
Serum Refrigerated, 2oC to 8oC 6 days
Frozen, -20oC 14 days
 
 
 
Test Code:
FT3

Order Name:
Free T3

 
Method detail:

 
 
Schedule:
Tested daily (24 hours)
 
 
Turnaround Time:
Specimen collected to reported within 2:00 hours (120 mins)
 
Performing Location:
Immunology, Laboratory Department Tel. 13227
 
Specimen Retention Time:
5 days
 
 
 
Test Code:
FT3

Order Name:
Free T3

 
 
Clinical Information:
Triiodothyronine (T3) is a thyroid hormone with a molecular weight of 651 daltons and a half-life in serum of 1.5 days.  T3 circulates in the blood as an equilibrium mixture of free and protein bound hormone. T3 is
bound to thyroxine binding globulin (TBG), prealbumin, and albumin. The actual distribution of T3 among these binding proteins is controversial as estimates range from 38-80% for TBG, 9-27% for prealbumin, and 11-35%
for albumin.  The binding of these proteins is such that only 0.2-0.4% of the total T3 is present in solution as unbound or free T3. This free fraction represents the physiologically active thyroid hormone. 

Free T3 is typically elevated to a greater degree than free thyroxine (T4) in Graves’ disease. Occasionally, free T3 alone is elevated (T3 thyrotoxicosis) in about 5% of the hyperthyroid population. In contrast, levels of free T4 are elevated to a greater degree than free T3 in toxic multinodular goiter and excessive T4 therapy.  Serum free T3 is useful in distinguishing these forms of hyperthyroidism. Free T3 may also be important in monitoring patients on anti-thyroid therapy where treatment is focused on reducing the T3 production and the T4 conversion to T3. Serum free T3 may also be useful in assessing the severity of the thyrotoxic state.
 
Reference Value:
1.71 – 3.71 pg/mL 
 
Clinical Reference:
  1. Manufacturer’s Reagent package insert Architect Free T3, March 2017, Abbott Ireland Diagnostic Division, Lisnamuck, Longford Co., Ireland
  2. Reference range: Bumrungrad hospital Verification of Reference range Interval (Method validation/Verification for Free T3)