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 are stable in original tubes for 24 hours 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
>24 hours Gold top
> 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
26-OCT-24 MS