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Epic Code LAB3077 Thyroid Function Cascade (TSH, reflex to TPO, Free T3, and/or Free T4, if indicated)

Important Note

  • TSH is performed. See Reflex Information to learn more. 
  • Method is Roche cobas Electrochemiluminescense Immunoassay.
  • Patient results determined by assays using different manufacturers for methods may not be comparable.

Test Name Alias

Thyroid Function Cascade | 6701

Interface Order Alias

11648

Specimen Requirements

Specimen Collection: Blood

 

Container(s): 4.5 mL Mint Green Top (Lithium Heparin Gel) or 5.0 mL Gold Top (Serum Separator-SST Gel)

Preferred Volume to Collect: 4.5 mL

Minimum Volume to Collect: 4.0 mL

Neonate Volume to Collect: 2.0 mL

Capillary collect ok? Yes

Microtainer acceptable: Yes

 

Collection Instructions:

  • After collection, gently invert tube 8-10 times.
  • Specimen should be processed within 2 hours – See Processing Instructions.

 

PROCESSING INSTRUCTIONS (LAB, OUTPATIENT, OR OFF-SITE COLLECTION)

Processed Specimen: Plasma or Serum

Centrifuge/Spin: Yes

Aliquot: Yes

 

Processing Instructions:

  • Plasma is preferred specimen type
  • Green Tube/Plasma: Centrifuge after collection. Minimum volume: 2.0 mL Plamsa
  • Gold Tube/Serum: Allow blood to clot for 30 minutes in a vertical position and centrifuge within 2 hours. Minimum volume: 2.0 mL Serum

Transport Temperature: Refrigerate

Specimen Transport Temperature

Refrigerate

Specimen Stability

Ambient: 8 hours

Refrigerated: 72 hours

Frozen: aliquot plasma/serum for longer storage

Laboratory Retention: 72 hours

Reflex Information

Reflex Criteria:

  • If the TSH is within the normal range (0.30-5.00 µIU/mL), no further testing will be performed.
  •  If the TSH is elevated (above 5.00 µIU/mL), a Free T4 and AntiTPO (anti-thyroid peroxidase antibody) will be performed as reflex tests.
  • If the TSH is decreased (below 0.30 µIU/mL), a Free T4 will be performed as a reflex test.
  • If the TSH is markedly decreased (below 0.10 µIU/mL), and the Free T4 is not increased (not above the upper limit of normal of 1.6 ng/dL), a Free T3 will be performed as an additional reflex test.

MEC Approved Reflex

Test Frequency

Available daily, usual TAT 1 day.

Reference Range

TSH

0 up to 3 days: 1.00 - 16.00 μIU/mL

3 days up to 1 year: 0.80 - 8.00 μIU/mL

1 year up to 10 years: 0.60 - 6.00 μIU/mL

10 years and up: 0.30 - 5.00 μIU/mL


Free T3

2.0 to 4.4 pg/mL.


Free T4

0 up to 3 days: 1.5 - 3.5 ng/dL

3 days up to 1 year: 0.9 - 2.0 ng/dL

1 year and up:  0.6 - 1.6 ng/dL
 

TPO

<35.0 IU/mL

 

Performing Department

Chemistry

Performing Department Laboratory Location

Corewell Health Reference Laboratory, Grand Rapids, MI

Methodology

Method is Roche cobas Electrochemiluminescense Immunoassay.
Patient results determined by assays using different manufacturers for methods may not be comparable.

CPT

84443

CDM Code

3018444301

Epic Test ID

1230101214

LOINC

TSH: 3016-3

Reviewed Date

3/7/2024