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Test Code TSHC Thyroid Cascade

Important Note

Plasma samples are not acceptable for testing.

The Thyroid Cascade is a reflex test.

When a Cascade TSH is ordered, testing starts with a TSH. If TSH is normal, testing ceases; TSH reported. If TSH is low a Free T4 is performed and reported (additional charge). Low TSH and high Free T4 indicate hyperthyroidism. Low TSH (<0.01 uIU/mL) and a normal or low Free T4 cascades to a Total T3 (additional charge). Low TSH and normal or low Free T4 indicates T3 toxicosis. High TSH cascades to Free T4 (additional charge). High TSH indicates hypothyroidism.

Specimen Information

Obtain specimen using standard phlebotomy techniques.

No special patient preparation is necessary.

 

Container Specimen Temperature Collect Vol Submit Vol Min Vol Stability
SST Serum Refrigerate 4.0 mL 1.5 mL 1.2 mL 7 days

Reject Due To:

- Moderate or Marked Hemolysis

- Specimen unlabeled or mislabeled

- Plasma submitted for testing

Instrumentation / Method

Ortho Vitros XT 7600 / See Individual Tests

Test Schedule / Analytical Time / Test Priority

Daily / Same Day / Not Available STAT

Reference Range

Male and Female:

See Individual Tests

CPT / LOINC

Meditech Medent LOINC CPT
CTSHS CTSHS 3016-3 84443