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Test Code TSHR TSH REFLEX CASCADE to FT4, T3F

Important Note

The results of this assay can be falsely lowered due to the consumption of Biotin.  Please instruct patients to discontiue the use of vitamins or supplements that contain Biotin 12hrs before blood draw.

Performing Location

Southwestern Vermont Medical Center

Collection Instructions

 Refer to venipuncture protocol

 

Collection Container

Gold top or Marble Red top vacutainer

 

Specimen Required/Volume

1.0 mL

Specimen Type

serum

Turn-Around Guidelines

Upon arrival daily

 

Thyroid Cascade testing that does not require T3 Free  testing are performed on the day of the order. Thyroid Cascade testing that require a  T3 Free, which are sent to a reference laboratory, will report out the results of the TSH and Free T4 to the clinician on the day of the order with the T3 Free following in 2 days from the reference laboratory.

 

STAT Availability:

 

Yes, unless a T3 Free is required

 

Reference Values

TSH: 0..47– 4.68 uIU/mL
Free T4: 0.8- 2.2 ng/dL
T3 Free  2.3 – 4.2 pg/mL
To review the Thyroid Cascade testing algorithm, refer to the Reflex Testing section of this manual.

Method

Refer to individual tests (TSH, Free T4 and T3 Free)

 

CPT

84443 - TSH

+ reflex Free T4 - 84439 as appropriate,

+ reflex T3 Free - 84481 as appropriate

 

LOINC

 3016-3 - TSH

(3024-7 - T4 Free reflex)

(3051-0 - T3 Free reflex)

Special Handling

Lab tech:

Separate and Refrigerate serum