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Epic Test Code LAB136 T3, Total: Serum

Performing Location(s)

BMC

Specimen Type

Serum

Preferred Container

Gold or Red top tube

Blood Tube Draw Volume

Min 50% draw volume  

Storage Requirements

Sample tubes should be centrifuged within 2 hours of collection 

Gold tops DO NOT ALIQUOT

Aliquot Red tops

See Causes of Rejection for temperature requirements.

Minimum Volume to Submit for Testing

1 mL Serum

  • Multiple test can be performed from this volume. For question please contact the lab at 547-3975.  

Transportation Needs

 Deliver specimen to laboratory within 1 hour of collection if unspun. If not possible see "storage Requirements". 

Causes for Rejection

Mislabeled or unlabeled specimen
Less than 50% draw for Vacutainer tubes

> 48 hours Refrigerated
>8 hours Room Temp
> 6 month Frozen
Hemolysis > 1000 mg/dL HgB
Lipemia > 1800 mg/dL Trig
Bilirubin > 10 mg/dL Bili
EDTA,NaF,Oxalate
High levels of Biotin
> 400 mg/dL Cholesterol

 

Limitations

Specimen hemolysis or turbidity may affect results.

Reference Values

Population Units Reference Range
All populations ng/dL 79.0-149.0

 

Days of Analysis

All

Available STAT

Yes

Methodology

Beckman AU/Dx Series

Additional Information

Thyroid function tests are ordered whenever there is suspected thyroid disease or for the management of patients on replacement therapy. The introduction of sensitive thyrotropin (sTSH) in the early 1990’s has transformed thyroid function testing from thyroxine-based strategies to sTSH strategies. The American Thyroid Association (ATA) and the National Academy of Clinical Biochemists (NACB) have recommended that serum sTSH level be the first test, complemented by an appropriate free thyroxine (FT4) estimate. This strategy represents the best and most efficient combination of blood tests for diagnosis and follow-up of most patients with thyroid disorders.

 

T3 is recommended for patients with suppressed sTSH and normal FT4. T3 is not recommended in patients with normal or increased sTSH.

 

Most thyroid testing is performed on out-patients. The ATA does not recommend thyroid screening in sick hospitalized patients, unless clinically significant thyroid disease is suspected.

 

This reflexive protocol has been approved by Drs. Hughes and Rockwell.

 

Accordingly, the Bassett Healthcare Clinical Laboratories will be providing reflexive thyroid function testing using the following algorithm.

If the TSH is normal, no further testing will be performed. (CPT 84443 will be billed)

 

If the TSH is > 3.00, a FT4 will be performed (CPT 84439 will be billed)

 

If the TSH is < 0.34, a FT4 will be performed (CPT's 84439 and 84480 will be billed)

 

If the TSH is < 0.34 and FT4 is normal, than a TT3 will be performed (CPT's 84439,84480 and 84443 will be billed)

 

 

 

A TSH will be performed. Subsequent/Additional testing will be performed based on the following algorithm.

 

 

 

Synonyms

Total Triiodothyronine (TT3)

CPT Code

84480

Last Updated

29-NOV-24 MS