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T4 (Free) and TSH (Ultrasensitive) Test

T4 (Free) and TSH (Ultrasensitive) Test

also known as: Free T4, Direct, Serum, Free Thyroxine, T4, Free, Direct, Serum

T4 is a Thyroid hormone which helps control rate of the energy that a human body use. T4 is also called as Thyroxine. TSH stimulates the Thyroid gland to produce T4 and T3 ( Tri- iodothyronine).

TSH is produced in a pituitary gland. TSH also helps to maintain the thyroid level in the body by reversing it with the help of Thyrotropin hormone produced by Hypothalamus. When the thyroid gland, pituitary gland and hypothalamus functions and sync up together the thyroid level is maintained in the human body. If Thyroid gland releases more T4 and T3 it results in Hyperthyroidism results in symptoms like Increased heart rate, Weightloss, weakness, tremor, Anxiety, and irritation of eyes and skin. If TSH is produced more it reverses the thyroid hormones (T4 and T3) results in Hypothyroidism results in symptoms like weight gain, cold intolerance, Fatigue and menstrual irregularity.

The TSH and T4 (free) test are always ordered together. It is essential to know the patient's medication. Some medication can affect the test results. The physician must be aware of it.

If the person in the case takes medicine for Hyperthyroid and Hypothyroid factors, two- month gaps are necessary for the both the test. No fasting is necessary for this test. Pregnancy also affects the Thyroid hormone level. Other medicines can also influence thyroid secretion.

This test is adequate to know the initial stage of Hypothyroid. Hypothyroidism can be treated by adjusting the hormone levels by inducing the T3 and T4 hormones. This method requires check-up for every 2 months.

Hyperthyroidism can be treated in early stage through this method of testing. The adverse level will end up in Thyroid gland removal and induce T3 and T4 hormones through medication. The results may be an initial check-up. Based on the results the physician suggests a further test or scan process.

These tests involve the blood sample. The preliminary questions about the previous test and medication should be asked. Make the person sit comfortably. Find the blood veins of the patient near elbow region. Tie up the elastic band above the elbow. It makes visibility of vein more firm. Inject the syringe and pull out enough amount blood required for the test. Press the cotton ball against the poked surface.

LimitationsFT4 may be increased with radiologic contrast agents, propranolol, amiodarone, and heparin. It may be decreased with carbamazepine (Tegretol®). Free T4 is a small part of total T4. Increased free T4 levels may occur in subjects with nonthyroid diseases. Such elevations are described as transient.2 Low values were reported in patients with nonthyroidal illness.3 Discrepancies in free T4 levels between methods are recognized.4 Reliability problems continue to be discussed with the direct (analog) methods.5 Results of kits intended to serve in place of equilibrium dialysis technique may differ from the reference method.
0.8 mL
Red-top tube or gel-barrier tube.
Type Gender Age-Group Value
Free T4 Ultrasensitive Tsh Blood
All age groups
4.5 - 11.7 mcg/dl
Average price range of the test is between Rs.100 to Rs.600 depending on the factors of city, quality and availablity.

Table of Content

What is T4 (Free) and TSH (Ultrasensitive) Test?
Preparation for T4 (Free) and TSH (Ultrasensitive) Test
Uses of T4 (Free) and TSH (Ultrasensitive) Test
Procedure for T4 (Free) and TSH (Ultrasensitive) Test
Limitations of T4 (Free) and TSH (Ultrasensitive) Test
Specimen Requirements
Normal values for T4 (Free) and TSH (Ultrasensitive) Test
Price for T4 (Free) and TSH (Ultrasensitive) Test
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Popular Questions & Answers

Hello doctor, Please help, very much nervous and worried. My period started on 30 Jan by 4 Pm and I had my blood test on 2 feb in morning by 10 Am and received my report in evening which show my FSH is 13.33 And LH is 6.50, Insulin fasting serum is 5.60, Prolactin serum is 13.63, T4 Free is 1.05 and TSH ultrasensitive is 2.049. Please tell me what my report tell and what problem I have related to fertility as I want to conceive. Please reply.

MBBS, DGO, MD, Fellowship in Gynae Oncology
Gynaecologist, Delhi
Hello doctor,
Please help, very much nervous and worried.
My period started on 30 Jan by 4 Pm and I had my blood test...
As per your reports you have a reduced ovarian reserve, i.e. the quality and quantity of egg produce is not good.. Your Prolactin and thyroid reports are normal. Also get your AMH test done. Since your age is also 30 yrs, so would suggest you to go for IVF.