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Test Name

Thyroid Cascading Reflex

CPT Code(s)

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: The Thyroid Cascading Reflex will only be performed on patients aged 20 years or older. Orders on patients younger than 20 will have a TSH only performed.

Methodology

Immunoassay

Reference Range(s)

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.

To view specimen requirements and codes please Select a regional laboratory.

Not sure which laboratory serves your office? Call us 866-MYQUEST (866-697-8378)

Reference ranges are provided as general guidance only. To interpret test results use the reference range in the laboratory report.

The CPT codes provided 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 payer being billed.

* The tests listed by specialist are a select group of tests offered. For a complete list of Quest Diagnostics tests, please refer to our Directory of Services.

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42525
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Thyroid Cascading Reflex
15102