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TSH w/ Rflx to Free T4

Important Note

*This test is orderable in Cerner as TSH w/ Rflx to Free T4

 

The results of this assay can be falsely elevated due to the consumption of Biotin. Please instruct patients to discontinue the use of vitamins or supplements that contain Biotin 12 hours before blood collection.

Specimen Requirements

Specimen Type: Blood
Container/Tube:

Preferred: Light-green top (lithium heparin gel)

Acceptable: Red top, serum gel

Specimen Volume: Full tube

Specimen Minimum Volume: 2 mL

Collection Instructions:

1. Send specimen in original tube.

2. If there is a delay in transport of >1 hour, centrifuge tube.

Stability

7 days Refrigerated

Reference Range

0.358-3.74 mcIntlUnit/mL

TSH results of 3.75 or greater will reflex to a Free T4.

Instrumentation

Siemens Dimension EXL

Methodology

Enzyme Immunoassay (EIA)

Test Schedule/Analytical Time/ Test Priority

Daily / Same day / Available STAT

CPT (s)

84443