Sign in →

Epic Test Code LAB3889 Thyroid Stimulating Hormone-Sensitive with reflex

Performing Location(s)

BMC,FOX,FTT,CRH,LFH,OCH

Synonyms

Thyrotropin Hormone, TSH

Specimen Type

Serum

Preferred Container

Gold or Red top tube

Blood Tube Draw Volume

Min 50% draw volume  

Minumum Volume to Submit for Testing

0.5 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". 

Storage Requirements

Sample tubes should be centrifuged within 2 hours of collection followed by transfer of the serum (red or gold top) to a labeled plastic, aliquot tube.

See Causes of Rejection for temperature requirements.

Avoid repeated freezing and thawing

Causes for Rejection

Mislabeled or unlabeled specimen
Less than 50% draw for Vacutainer tubes
>48 hours refrigerated
>8 hours room tempature
>3 montsh frozen
Plasma Specimen
Hemolysis > 1000 mg/dL HgB
Lipemia > 3300 mg/dL Trig
Bilirubin > 40 mg/dL Bili
EDTA, NaF,Citrate, Oxalate

Oxalate

Limitations

See individual tests (TSH, Free T4, T3)

 

Patients taking biotin supplements in excess of the daily recommended allowance may cause falsely elevated results.

Reference Values

TSH Reference Range
Population Units Reference Range
Newborn - 1 month uIU/mL 0.80 - 10.00
General (> month old)* uIU/mL 0.41-4.50

 

T4 Free Reference Range
Population Units Reference Range
All populations ng/dL 0.6-1.3

 

Total T3 Reference Range
Population Units Reference Range
All populations ng/dL 79.0-149.0

 

Reflex Testing

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 > 4.50, a FT4 will be performed (CPT 84439 will be billed)

 

If the TSH is < 0.41 a FT4 and a TT3 will be performed (CPT's 84439,84480 and 84443 will be billed)

 

 

 

 

 

 

 

Days of Analysis

All

Available STAT

Yes

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 Endocrinology.

 

Methodology

See individual tests (TSH, Free T4, T3)

CPT Code

84439 - Free T4

84480 - T3

84443 - TSH

Last Updated

25-Apr-22 BHD