Lab comparison
Thyroid-stimulating Hormone (TSH) and Free T4: 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 | 36127 | 224576 | A518-3 |
| Primary tube | Serum separator tube (SST) | Red-top tube, gel-barrier tube, or green-top (lithium heparin) tube. Do not use oxalate, EDTA, or citrate plasma. | SST Tube |
| Specimen type | Serum | Serum (preferred) or plasma | 1 mL SST Tube |
| Patient prep | Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks after angiography. According to the assay manufacturer Siemens: samples containing fluorescein can produce falsely depressed values. | Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks after angiography. According to the assay manufacturer Siemens: samples containing fluorescein can produce falsely depressed values. | Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks after angiography. According to the assay manufacturer Siemens: samples containing fluorescein can produce falsely depressed values. |
| Turnaround time | Not stated | Not stated | Turnaround Time 1 DAY |
| Minimum volume | Minimum Volume 0.7 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 Thyroid-stimulating Hormone (TSH) and Free T4?
The Quest Diagnostics order code for Thyroid-stimulating Hormone (TSH) and Free T4 is 36127.
What tube color does LabCorp use for Thyroid-stimulating Hormone (TSH) and Free T4?
LabCorp uses a Red-top tube, gel-barrier tube, or green-top (lithium heparin) tube. Do not use oxalate, EDTA, or citrate plasma. for Thyroid-stimulating Hormone (TSH) and Free T4.
Does Thyroid-stimulating Hormone (TSH) and Free T4 require fasting?
Thyroid-stimulating Hormone (TSH) and Free T4 patient prep: Specimen collection after fluorescein dye angiography should be delayed for at least 3 days. For patients on hemodialysis, specimen collection should be delayed for 2 weeks after angiography. According to the assay manufacturer Siemens: samples containing fluorescein can produce falsely depressed values.. 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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