T3, Free
Quest Diagnostics
Sample type: Serum
Requires fasting: No
Phlebotomy required
Details
This test is typically ordered if patients exhibit symptoms of hyperthyroidism or if other thyroid test results, like TSH or FT4, are unusual.
- Free T3
Estimated days for results: Results should be available in 2 - 5 business days after the sample is collected
Details
The Free T3 (FT3) test measures the level of triiodothyronine (T3) in the blood that is not attached to proteins. This test is important for diagnosing and managing hyperthyroidism and understanding thyroid health, especially when there might be issues with thyroid hormone-binding proteins. It's often used together with tests for thyroid-stimulating hormone (TSH) and free T4 (FT4) to get a full picture of thyroid function.
What patients is this test right for?
This test is typically ordered if you have symptoms of hyperthyroidism or if other thyroid test results, like TSH or FT4, are unusual. Symptoms of hyperthyroidism include:
- Weight loss
- Rapid heartbeat
- Nervousness or irritability
- Sweating more than usual
- Feeling hot
- Changes in menstrual patterns
What type of sample is required for this test?
1 mL serum. A blood draw is needed.
3–5 business days
<1 Month Not established
1-23 Months 3.3-5.2 pg/mL
2-12 Years 3.3-4.8 pg/mL
13-20 Years 3.0-4.7 pg/mL
>20 Years 2.3-4.2 pg/mL
1-23 Months 3.3-5.2 pg/mL
2-12 Years 3.3-4.8 pg/mL
13-20 Years 3.0-4.7 pg/mL
>20 Years 2.3-4.2 pg/mL
Blood Draw Options with Fullscript
Fullscript offers several convenient phlebotomy options to complete your lab testing:
Quest Diagnostics Patient Service Centers (PSC)
- Location: Visit a nearby Quest Diagnostics Patient Service Center.
- Cost: $10 sample collection fee (paid during lab order checkout).
- Scheduling: Schedule your appointment here. Appointments are recommended to reduce wait times. Walk-ins are accepted, but may experience delays. Aim to arrive 10 minutes before your appointment.
- Collection Instructions:
- Bring a valid ID.
- Bring your digital or printed requisition form, available in the Labs tab of your Fullscript account.
- Check-in: Scan the QR code from your confirmation email or follow kiosk instructions.
- More Info: Quest Diagnostics blood draw guide
Getlabs Mobile Phlebotomy
- Location: Sample collection at your home or office.
- Cost: $85 sample collection fee (paid during lab order checkout).
- Availability: Available in most locations – enter your ZIP code during checkout to confirm.
- Scheduling: Schedule your appointment here through your Fullscript account.
- Collection Instructions:
- Have your digital or printed requisition form and valid ID ready.
- Your phlebotomist will contact you by phone to coordinate arrival.
- More Info: Getlabs blood draw guide
Specimen
- Preferred Specimen(s): 1 mL serum
- Alternative: NA
- Minimum Volume: 0.5 mL
- Collection Instructions: NA
Storage and shipping instructions
- Transport Container: Serum separator tube (SST)
- Transport Temperature: Room Temperature
- Specimen Stability:
- Room temperature: 7 days
- Refrigerated: 7 days
- Frozen: 28 days
- Reject Criteria: NA
State restrictions:
Patient can't order this test if they are located in Hawaii, Puerto Rico, New Jersey, New York, or Rhode Island
