TSH (Ultrasensitive)/ TSH-U Test

TSH test is done to: 

1. To identify overt and subclinical thyroid problems.
2. To keep track of thyroid replacement therapy patients.
3. To check for congenital hypothyroidism in newborns.
4. To check for thyroid symptoms, such as an enlarged thyroid or thyroid nodule.

TSH ultrasensitive test measures levels of TSH in blood.

The test requires a blood sample. An elastic band is tightly tied to the upper arm. The patient is then asked to make a fist. This helps to fill the veins with blood. A needle is inserted into the vein after cleaning the skin with an alcohol swab. A blood sample is collected using a vacutainer. A slight prick may be felt upon inserting the needle. Tenderness or bruising, if any, usually resolves in some time.

• High TSH & high FT3/FT4: Thyroxine replacement therapy; pituitary adenoma; drugs like heparin, amiodarone, beta blockers, steroids; neonates; resistance to thyroid hormones
• High TSH & low FT3/ FT4: Autoimmune thyroiditis, thyroidectomy, post-radiation, iodine deficiency, thyroid infiltrating tumour/ amyloid
• Low TSH & Low FT3/ FT4: Central hypothyroidism, non-thyroidal illness
• Low TSH & High FT3/ FT4: Grave's disease, toxic multinodular goitre, toxic adenoma, thyroiditis, drugs, hyperemesis gravidarum & hydatiform mole, congenital hyperthyroidism

The pituitary gland produces thyrotropin, often known as thyroid-stimulating hormone (TSH). It influences the thyroid gland to increase thyroxine (T4) and triiodothyronine (T3) production. These two thyroid hormones regulate several growth and metabolic processes in the body.

This test is recommended for people suffering from symptoms of hyperthyroidism or hypothyroidism.

The following are signs of hyperthyroidism:

• Loss of weight.
• Fast heartbeat.
• cold sweat
• Trembling.
• Perspiration.
• Panic.
• Increased awareness of heat.

Patients with hypothyroidism experience:

• weight gain
• abnormal menstrual cycles
• dry and flaky skin
• weariness
• sluggish heartbeat
• increased susceptibility to cold
• despair
• dry and thin hair

Regular TSH level monitoring in thyroid disorder patients is also necessary to adjust the medication dosage depending on the condition of the patient.

Since the testing can be performed at any time of the day, fasting is not necessary. Your doctor should be aware of any medications that you are taking and any X-rays or tests that required the administration of iodine dye 4 to 6 weeks prior to taking this test. These may have an impact on the test results. You may get advice from your endocrinologist if you need to take any extra precautions. 

The normal range for this test is 0.3 - 5U/ml across all age groups and sexes. However, the normal range may vary depending on age, sex and methodology used in the lab.

TSH (Ultrasensitive) is a more accurate and sensitive test than a regular TSH test.

Hypothyroidism is characterized by an underactive thyroid gland leading to low thyroid hormone production. Hyperthyroidism is characterized by an overactive thyroid gland that produces thyroid hormones in excess. Both are thyroid disorders that need to be treated with medications and lifestyle changes.

Grave's disease, also known as toxic diffuse goitre, is a kind of hyperthyroidism that occurs due to an autoimmune condition. It requires rapid treatment.

Depending upon your test results and your symptoms, your doctor may order additional tests, such as:

• T3-total
• T3-free
• T4-total
• T4-free
• Thyroid hormone binding globulin (THBG) test
• Thyroid profile test.

• Thyrotropin Test  
• TSH Ultrasensitive Test
• Thyroid Stimulating Hormone Test
• Ultrasensitive Thyroid Stimulating Hormone Test