They're usually ordered with TSH. Call 8872524007 to book.
What the Free T3/T4 test checks
Free T4 (FT4) is the unbound form of thyroxine, the main hormone the gland releases. Free T3 (FT3) is the unbound form of triiodothyronine, the more active hormone, much of it made from T4 in other tissues.
The main carrier protein, TBG, rises in pregnancy and with oestrogen tablets, and can fall in liver or kidney disease. Total hormone levels move with it. Free levels mostly don't, which is the whole point of measuring them.
Why your doctor may order it
The most common reason is an abnormal TSH test. Free T4 then shows whether the thyroid is truly underactive or overactive, or whether the change is subclinical.
Doctors prefer free hormones in pregnancy, in women on birth control pills, and when following treatment for an overactive thyroid. Free T3 is useful when an overactive thyroid is suspected but free T4 is normal, a pattern called T3 toxicosis. A free T4 test also matters when the pituitary itself is the concern, because TSH can't be relied on then.
How to prepare
No fasting is needed. If you take a thyroid tablet, ask your doctor whether the sample should be taken before the day's dose, since free T4 can rise for a few hours after it.
Biotin can cause falsely high free T4 and free T3 readings on many analysers, which can look like an overactive thyroid. Tell us if you take it, and ask your doctor whether to stop it for a few days beforehand. Heparin injections can also distort free T4.
Sample type and report time
Blood from an arm vein, collected in a serum tube (red or yellow cap). Same-day report if the sample reaches us by about 11 am. Expectant mothers often prefer home sample collection.
Understanding your results
Free hormone ranges depend heavily on the method used, and pregnancy has its own limits. The range printed on your report is the one that applies, because ranges vary by lab and method.
Low free T4 with a high TSH fits an underactive thyroid. High free T4, free T3 or both with a suppressed TSH fits an overactive one. Low free T4 with a low or normal TSH can point to a pituitary problem, or simply to recent serious illness.
Results that don't match each other, or don't match how the person feels, are sometimes from interference such as biotin or antibodies. Your doctor reads them with your symptoms, the thyroid profile and other tests.
FAQ
What is the difference between T4 and free T4?
Total T4 counts bound and free hormone together. Free T4 counts only the active unbound part.
Is there a free T3 test near me in Banur?
If you're searching for a free T3 test near me in Banur, you can walk in at our M.C. Road lab from 7 am, or ask for collection at home.
Do I need free T3 as well as free T4?
Not always. Many doctors start with TSH and free T4 and add free T3 only when an overactive thyroid is suspected.
Why are free hormones checked in pregnancy?
Pregnancy raises carrier proteins and pushes total T4 up, so free levels give a truer picture.
Book at Alpha Laboratory
Bring your TSH report if it was done elsewhere, so the free T3 test and free T4 can be read against it. Call 8872524007, WhatsApp us or write via the contact page.