Thyroid Cascading Reflex [15102X]

Test Code
18698


CPT Codes
84443

Includes
The Thyroid Cascading Reflex begins with a TSH.
If the TSH result is abnormal, T4, Free will be performed at an additional charge (CPT code(s): 84439).
If the TSH is elevated and the T4, Free is either normal or low, TPO Antibodies will be performed at an additional charge (CPT code(s): 86376).
If the TSH is low and the T4, Free is either normal or low, T3, Free will be performed at an additional charge (CPT code(s): 84481).

Note: This assay should only be ordered on patients 1 year of age or older. Orders on patients younger than 1 year will have a TSH only performed.


Preferred Specimen
4 mL serum collected in a red-top tube (no gel)


Minimum Volume
2 mL


Instructions

This assay should only be ordered on patients 1 year of age or older. Orders on patients younger than 1 year will have a TSH only performed.



Transport Temperature
Refrigerated (cold packs)


Specimen Stability
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days


Methodology
Immunoassay (IA)

Setup Schedule
Set up: Daily; Report available: 2 days


Reference Range
Premature Infants (28-36 Weeks)  
  1st Week of Life 0.20-27.90 mIU/L
Term Infants (>37 Weeks)  
  Serum or Cord Blood 1.00-39.00 mIU/L
  1-2 Days 3.20-34.60 mIU/L
  3-4 Days 0.70-15.40 mIU/L
  5 Days-4 Weeks 1.70-9.10 mIU/L
  1-11 Months 0.80-8.20 mIU/L
  1-19 Years 0.50-4.30 mIU/L
  ≥20 Years 0.40-4.50 mIU/L
Pregnancy  
  First Trimester 0.26-2.66 mIU/L
  Second Trimester 0.55-2.73 mIU/L
  Third Trimester 0.43-2.91 mIU/L

TSH levels decline rapidly during the first week of life in most children, but may remain transiently elevated in a few individuals despite normal free T4 levels. For proper interpretation of an abnormal TSH from a newborn thyroid screen, a Free T4 by Dialysis (test code 35167) or Total T4 (test code 867) should be considered.


Clinical Significance
The Thyroid Cascading Reflex order code that will act as an aid to physicians in the diagnosis of common adult thyroid disorders. The initial results of a TSH will determine further reflex orders of T4, Free, TPO Antibodies and T3, Free orders and provided an interpretation based upon the results of the reflexed tests.


Performing Laboratory
Quest Diagnostics Nichols Institute
14225 Newbrook Drive
Chantilly, VA 20153




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.