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- Ordering Info
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Thyroid Cascading Reflex
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.
Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks. According to the assay manufacturer Siemens: "Samples containing fluorescein can produce falsely depressed values when tested with the Advia Centaur TSH3 Ultra assay. "
4 mL serum
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.
Serum Separator Tube (SST®)
Room temperature: 4 days
Refrigerated: 7 days
Frozen: 28 days
|Quest Diagnostics - California Region|
|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|
|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.
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.
The Result and LOINC information listed below should not be used for electronic interface maintenance with Quest Diagnostics. Please contact the Quest Diagnostics Connectivity Help Desk for more information at 800-697-9302.NOTE: The codes listed in the table below are not orderable Test Codes.
|Result Name||LOINC Code||Component Name|
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.
LOINC assignment is based on a combination of test attributes, including the method used by the performing laboratory. For tests not performed by Quest Diagnostics, codes are assigned by the performing laboratory.
* 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.