What this test is
Most thyroxine in blood is bound to carrier proteins, so total T4 reflects those protein levels too. Pregnancy, oral contraceptives, and liver or kidney disease can alter the result.
Category: Thyroid Function
T4
Total T4 measures thyroid hormone both bound to carrier proteins and free. It is used when additional information about thyroid production is needed.
What it is used for, and who should test
- Assessing thyroid hormone production when free T4 is unavailable for laboratory reasons
- Following treatment response in selected cases at a doctor's request
- Supporting interpretation of TSH alongside the patient's symptoms
Sample and preparation
- Sample
- 2-3 mL of blood in a serum tube
- Preparation
- No fasting required. Mention pregnancy, oral contraceptives or medicines that affect blood proteins.
Where to get tested
Samples are collected and results issued at S.F. Laboratory, the in-house laboratory of BK5 Med Health Clinic in Don Hua Lo, Chon Buri. No appointment is needed; walk in during opening hours.
- Sample collection at BK5 Clinic, 149/6-7 Don Hua Lo, Chon Buri District, Chon Buri 20000
- Open Monday-Friday 08.30-20.00 and Saturday 08.30-17.00
- Ask questions or book ahead on LINE @824xsgsj or call 063-223-6161
The information on this page is general knowledge to support your decisions and is not personal medical advice. Interpreting results and planning treatment requires assessment by a doctor. Please consult our medical staff before deciding on testing or treatment.
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Thyroid Function
Frequently asked questions about this test
Should I choose total T4 or free T4?
Doctors usually prefer free T4 because it is independent of carrier proteins, but total T4 can still add useful information in specific situations.
Does pregnancy change total T4?
Yes. Carrier proteins increase in pregnancy, raising total T4, so pregnancy-specific ranges or free T4 are used.
How should I prepare for T4?
No fasting required. Mention pregnancy, oral contraceptives or medicines that affect blood proteins.
How long do results take?
About 1 day, depending on the laboratory workload that day. Our staff will confirm the collection time when you are served.
Where can I have this test done?
Samples are collected and results issued at S.F. Laboratory, the in-house laboratory of BK5 Med Health Clinic in Don Hua Lo, Chon Buri. No appointment is needed; walk in during opening hours.
How much does T4 cost?
Prices are not shown on this website. Ask for pricing and packages on LINE @824xsgsj or call 063-223-6161.
Contact us
Book a visit or ask a question
Add us on LINE @824xsgsj to ask about tests and pricing, or fill in the form below and our team will get back to you as soon as possible.
Phone
063-223-6161LINE Official
@824xsgsj
Address
149/6-7 Don Hua Lo, Chon Buri District, Chon Buri 20000, Thailand
Get directions (Google Maps)Opening hours
- Monday - Friday
- 08.30 - 20.00
- Saturday
- 08.30 - 17.00