Lab comparison
Triiodothyronine (T3), Free: Quest vs LabCorp vs BioReference, tube, code & requirements
. This page shows collection requirements for all three major reference labs in one view, so you don’t have to cross-check three portals.
Always verify against your lab’s current collection manual before drawing.
Every value on this page is verified by a nurse practitioner in active clinical practice, not scraped from an automated source.
| Requirement | Quest Diagnostics | LabCorp | BioReference |
|---|---|---|---|
| Test code | 34429 | 010389 | 0271-7 |
| Primary tube | Serum separator tube (SST) | Red-top tube, gel-barrier tube or green-top (lithium heparin) tube | SST Tube |
| Specimen type | 1 mL serum | Serum (preferred) or plasma | 2 mL SST Tube |
| Patient prep | This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample. | This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample. | This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample. |
| Minimum volume | Minimum Volume 0.5 mL | Minimum Volume 0.7 mL (Note: This volume does not allow for repeat testing.) | Qty 1 |
Frequently asked questions
What is the Quest Diagnostics order code for Triiodothyronine (T3), Free?
The Quest Diagnostics order code for Triiodothyronine (T3), Free is 34429.
What tube color does LabCorp use for Triiodothyronine (T3), Free?
LabCorp uses a Red-top tube, gel-barrier tube or green-top (lithium heparin) tube for Triiodothyronine (T3), Free.
Does Triiodothyronine (T3), Free require fasting?
Triiodothyronine (T3), Free patient prep: This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.. Always confirm with the ordering lab before the draw.
Data provenance
Source: Quest Diagnostics specimen collection manual, LabCorp directory of services, and BioReference laboratory collection guide.
Verified by: a licensed nurse practitioner in active clinical practice. Values are reviewed against each lab’s published collection requirements. Always confirm against your lab’s current manual before drawing.
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