Wednesday 7 September 2011

Laboratory test- Thyroid Function Test(TFT)

Thyroid

Thyroid is a butterfly shaped gland located infront of the neck ,just below the voice box.Thyroid normally weighs 15 to 25 grams.It is known that it starts functioning even before birth.Thyroid secretes two metabolically important hormones,called T3 & T4 that are vital for physical and mental growth.

Thyroid Hormones

T3 & T4,the thyroid hormones,control various metabolic activities essential for energy,growth and development of the body.These two hormones are required every minute by every organ,tissue and cell.The thyroid in specific quantities should secrete them,and if more or less than the required quantity is produced,certain health complication arise.

Thyroid Controller

Another endocrine gland called the pituitary secretes a hormone called thyroid stimulating hormone(TSH),which acts on the thyroid specifically and directly.TSH stimulates and controls various steps involved in the synthesis  and secretion of thyroid hormones.TSH senses existing thyroid hormones levela and works as required to maintain the desired levels.

Role of  Iodine in Thyroid

The thyroid hormones are made up of iodine.It thus place a crucial role in thyroid functioning.Iodine deficiency leads to thyroid disorders.

Thyroid Disorder

Basically two types of disorders.

1. Goiter,which is an abnormal size and structure of the thyroid gland. Studies like FNAC,Ultrasound  and nuclear scanning can help in knowing the details of such  abnormal  growth.

2. Thyroid dysfunction, which is the under or over functioning of the thyroid gland.This may happen even without  a Goiter.Abnormally low secretion of thyroid hormones is called hypothyroidism(Under functioning)which leads to decreased metabolic activities and related disorders.Abnormally high secretion of thyroid hormones is known as hyperthyroidism(Over functioning).This leads to incresed metabolic activities and related disorders.These disorders can be diagnosed by doing simple and quick blood test.Once diagnosed these abnormal conditions can be brought to perfect normalcy with the help of proper medication within a few weeks or a month.

Thyroid Evaluation

Patholigical Laboratort test to evaluate patients thyroid status.
  1. Triiodothyronine(T3)
  2. Thyroxine(T4)
  3. Thyoid stimulating Hormone(TSH)
  4. Free Thyroxine(FT4)
  5. Free Triiodothyronine(FT3)
  6. Anti Thyroglobulin antibodies(ATG)
  7. Anti microsomal antibodies(AMA)

Thyroid biochemistry,Physiology and Pathophysiology are quite complicated.The above seven tets are used in combinations to study the function of the gland and cause of the disfunction.However doing FT3,FT4 and TSH is the most used combination by doctors.These sre the basic thyroid tests,which reveal the concentration of the thyroid hormanes in the blood stream and the diagnosis thereof.

Indications for Thyroid Test
  1. Women above 40 years of age
  2. Women who has recently given birth
  3. Those who have high Cholesterol.
  4. Those who have lost or gained more than two kilos in two to threee months
  5. Those who feel exhausted and fatigued
  6. Those with abnormalities in mestrual history.
  7. Those suffering from infertility
  8. Those with a family history of Thyroid disease

Relationship between Weight & Thyroid

What we eat should be converted into energy for a normal and healthy life.In hypothyroidism,due to paucity of th hormones the energy conversion is reduced.Hence fat accumalation and weight increase are very common in the hypothyroid patients.Once diagnosed and treated,however,the supllemented thyroid hormones tune up the metabolic system and hence the excess weight will be reduced.In hyperthyroidism the hormones are in excess.So they are burn out the energy more than required resulting in heavy loss of weight.Some patients even lose 10 kgs in just a month.Thus weight and stamina are two main criteria in thyroid evaluation.