| 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 # |
Thyroid Cascading Reflex [15102X]
Test Code18698
CPT Codes
84443
Includes
The Thyroid Cascading Reflex begins with a TSH.
If the TSH result is abnormal, then 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, then 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, then 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.
If the TSH result is abnormal, then 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, then 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, then 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
Transport Temperature
Room temperature
Specimen Stability
Room temperature: 7 days
Refrigerated: 7 days
Frozen: 28 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 |
