Thyroid Cascade THCS
One 5 mL gold (SST) top tube. Also acceptable: heparinized plasma.
1 mL serum at 2-8ºC.
|Stability||Refrigerated: 7 days.|
|CPTCode||84443 (If reflexed, 84439 and 84481)|
TSH is performed. If the TSH is abnormal, a Free Thyroxine is performed. If Free Thyroxine is normal, then Free T3 is performed.
TSH may be falsely decreased and Free T4 and Free T3 may be falsely elevated in patients taking over-the-counter biotin supplements.
|Preferred Specimen Collection Device(s)|