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HelpTest Code LAB127 Free T4 (Free Thyroxine)
Performing Laboratory
Asante Rogue Regional Medical Center / Asante Three Rivers Medical Center / Ashland Community Hospital
Specimen Minimum Volume
0.5 ml
Billing Code
2070589
Methodology
Chemiluminescence (CLIA)
Reasons for Rejection
Hemolysis
Quantity not sufficient (QNS)
Lack of Two Patient Identifiers:
1-Patient's First & Last name
2-Patient's Date of Birth
Day(s) Test Set Up
Monday through Sunday
Routine – same day
ASAP – 2 hours after receipt of specimen in lab
STAT – 1 hour after receipt of specimen in lab
Test Classification and CPT Coding
84439 - Thyroxine; free
Additional Information
Free Thyroxine (FT4) is the metabolically active form of
Thyroxine (T4). FT4 is superior to Total T4 due to the
lack
of interference from thyroid binding globulins. It is
elevated in hyperthyroidism (Thyrotoxicosis, Graves Disease) and
decreased in hypothyroidism.
Specimen Transport Temperature and Stability
Centrifuge collection tube and refrigerate within 2 hours of collection
Primary tube: Spun SST stable 24 hours at 2° to 8° C
Serum stable 48 hours if aliquoted and refrigerated at 2° to 8° C
Performing Department
Chemistry