Antithyroglobulin Antibody Test
Anti-thyroglobulin Antibody Test
The Thyroid gland is an endocrine gland which is present in the neck region in the human body. It plays an important role in controlling the metabolism process by releasing the hormones essential for the process to take place. It is responsible for the production of various proteins. Thryoglobilin is one such protein produced by the Thyroid gland. This protein is crucial for the synthesis of the Hormones of the Thyroid gland.
Certain autoimmune disorder is seen to destroy the process of the formation of this protein. The attack of the immune system to the healthy cells and tissues in a person’s body leads to the occurrence of the autoimmune disorders. If the attack is done to the Thryoglobilin protein then a corresponding antibody known as Antithyroglobulin is formed in response to the attack. The Antithyroglobulin antibody test is useful to monitor the presence of this antibody called Antithyroglobulin in the blood sample of a person.
- This test is also known as by names such as TgAb, Thyroid antibody, ant microsomal antibody, TPOAb, antithyroid antibody, Anti-TPO and TBII test.
This test measures the presence of antibodies against the Thyroglobulin protein.
Antibodies are proteins formed by the immune system if it detects certain bacteria, fungi, parasites called the antigen within the body which are harmful for the body.
The formation of antibodies is seen in when the immune system is not able to differentiate between the healthy and harmful cells in the body and considers the healthy cells as harmful and attacks them. The role of each type of antibody is specific and they bind with the specific antigen only and protect the body against them by attacking them.
The higher levels of Antithyroglobulin indicate the presence of disease such as Hashimoto thyroiditis (destruction of the cells of Thyroid gland), Differentiated thyroid cancer and chronic urticarial disease.
The 3 types of auto antigens of thyroid gland responsible for the production of antibodies during the autoimmune disorder of the Thyroid gland are as follows:
- Thyroglobulin( Grave disease or Hashimoto thyroiditis)
- Thyroid microsomal antigen
- Thyrotropin receptor.
There are certain conditions where the presence of lower to moderate level of Thyroglobulin antibody is seen which are as under:
- Rheumatoid arthritis,
- Systemic Lupus Erythematosus(SLE)
- Thyroid Carcinoma,
- Chronic Urticaria,
In around 10-20% healthy individual the presence of the serum antibodies to thyroglobulin is seen.
The Thyroglobulin autoanitgen is a glycoprotein which is secreted in the follicle cells present in the Thyroid gland. It is a prohormone and consists of, iodinated tyrosine moieties which is responsible for the formation of thyroxine and triiodothyronine active hormones. The amount of Thyroglobulin present in a healthy individual is seen to be up to 30 ng/mL
The thyroid origin of cell specific Thyroglobulin is proved by the presence of it in Biopsy specimen. Apart from that the serum thyroglobulin testing is a crucial test which can provide useful information related with the occurrence of metastatic, recurrent, or residual disease in patients having differentiated thyroid cancer.
People suffering from cancer of the Thyroid gland i.e around 20% and 10% of general population in them the antithyroglobulin antibodies are detected and this can prove to be difficult and cannot be reliable for clinical diagnosis of Thyroglobulin values which is obtained along with the Antithyroglobulin antibodies.
What Indications lead for the Thyroglobulin antibodies measurement?
There are various indications which call for the measurement of Throglobulin antibodies which are summarized as under:
- To monitor the differentiated Thyroid cancer:
With the help of Serum Thyroglobulin measurement relevant information regarding the presence or absence of residual, recurrent or metastatic condition related with differentiated Thyroid cancer can be easily identified. The Thyroglobulin antibodies are detectable in up to 20% patients who suffering from Thyroid cancer and this can affect the Throglobulin assay and makes it unreliable for the treatment of Differentiated Thyroid Cancer. The significance of thyroglobulin antibody values after surgical and radioiodine ablation for differentiated thyroid cancer is unclear, but a persistence of thyroglobulin antibodies indicates possible residual thyroid tissue and an increased risk of recurrence. Another cause of persistent thyroglobulin antibodies (even up to 20 y in some individuals without detectable differentiated thyroid cancer) is coexistent autoimmune thyroid disease.
Thyroglobulin antibody and Ant microsomal antibody are the two types of antithyroid antibodies seen in Hashimoto Thyroiditis. Ant microsomal antibody is the more specific of the two antibodies for the autoimmune Thyroiditis as compared with the less specific antithyroglobulin antibodies. The presence of the antithyroglobulin antibodies in the absence of the other antibodies which is ant microsomal antibody is not enough to authorize the diagnosis.
To determine the presence of disease called Hashimoto Thyroiditis a study was conducted with around 2000 patients who had both the antimicrosomal and antithyroglobulin antibodies .In all these patients majority or 99% had the antimicrosomal antibodies but less than half around 35% were positive for the antithyroglobulin antibody. The conclusion of the study was that both test cost huge and is of no diagnostic use. Thyroglobulin antibody testing was not suggested for identifying the Hoshimoto Thyroiditis.
The chances of occurrence of the Thyroid autoantibodies increases in people suffering from Chronic Urticaria which is around 10-33% but the occurrence in the general population is around 3-6%
The patients suffering from Hashimoto Thyroiditis the frequency of occurrence of the condition of Urticaria increases. In certain cases of Chronic Urticaria the working of Thyroid autoantibodies takes place by the formation of Immune complexes, complement activation or the initiation of the secretion of Proinflammatory mediators.
This stain demonstrates a positive anti-thyroglobulin antibody test
The Occurrence of Thyroid disease is quite common. The blood sample of the patient needs to be diagnosed if the doctor feels the patient have this disease. The test includes the testing for the antibodies such as anti-thyroid peroxidase (anti-TPO) antibodies and hormones such as thyroid stimulating hormone (TSH) levels and levels of thyroid hormones both the T3 and T4in the blood sample of a person.
The other significant test includes: Anti-thyroglobulin antibodies test which is helpful in diagnosing the variety of disorders of Thyroid gland and will help in proper evaluation of the functioning of this gland. The antibodies are molecules of proteins manufactured in the blood cells known as lymphocytes which in turn get stimulated to form antibodies in response to the presence of foreign particles known as antigens. . Every antibody is active against a particular type of antigen only and combines with it to form antigen antibody complex to make the antigen inactive. It is seen that sometimes body starts manufacturing antibodies against its own body like the anti-thyroglobulin antibody.
The occurrence of these antibodies is seen in cases where an injury/inflammation of the thyroid gland is seen. These antibodies can prove fatal and can destroy the thyroid gland. The production of Thyroglobulin takes place exclusively in the epithelial cells of the thyroid gland. The combination of iodine and Tyrosine (a kind of amino acid found in the Thyroglobulin) takes place to form the hormones of Thyroid gland known as Thyroxine(T3) and Triiodothyronine(T4).Both the hormones are essential for carrying out almost all the metabolic activity within the body.
In a variety of conditions a positive result is seen for the antibodies known as antithyroglobulin antibodies such as .Hashimoto's thyroiditis, hypothyroidism, Grave's disease, Thyrotoxicosis, Myxedema or Thyroid cancer. The increase in these antibodies is seen in other conditions such as Diabetes, Systemic lupus erythematosusor Pregnancy The presence of Antithyroglobulin antibodies in healthy individual is also detected .The occurrence of Thyroid disease in healthy people with positive antithyroglobulin is a difficult predication to be made. It
There is a connection between the capacity to conceive and antithyroglobulin antibody. A higher levels antithyroglobulin antibody present in the expecting mothers can be fatal as it can lead to Miscarriage or can be infertile. Other than that it is seen that this antibody can also affect the implantation of the embroyo in the mother’s womb. The cause behind such condition is not clear and can be attributed with the presence of genes responsible for the autoimmune disease.
The levels of this antibody are observed very closely during the condition of Thyroid cancer. The levels of it are also monitored frequently if someone has undergone the surgery for the removal of cancerous thyroid gland. If someone has undergone a treatment with radioactive iodine too then the levels need to be checked .The treatment with this antibody is also given during the condition known as overactive thyroid gland.
Various factors need to be considered for detecting the disease of the Thyroid gland which is blood test, biopsies, imaging and other evaluations of clinical reports.
But the most prevalent test for the Thyroid disease is the blood test which is used to determine the level of TSH or thyroid stimulating hormone in the blood sample of a person. Any abnormal levels i.e an abnormal rise or fall in the level of this hormone can lead to the condition known as Hyperthyroidism and Hypothyroidism respectively.
Why is Antithyroglobulin Ab test ordered?
The physician can order this test
- If someone shows symptoms such as fatigue, a sudden gain of weight, drying of the skin or during constipation. Other than that doctor can order the test during the disease of Goiter where the enlargement near the neck area or thyroid gland is seen.
- To detect the presence of certain autoimmune disorder, such as Graves’ disease or Hashimoto thyroiditis
- To detect the problems related with the Thyroid glands-The antithyroglobulin antibodies can cause severed destruction of the thyroid gland and the probability of it rises during the condition of inflammation /injury related done to the thyroid gland.
Human Thyroid stained with anti-Thyroglobulin antibody
This test is very useful for the diagnosis of the Autoimmune disorders basically related with the Thyroid gland and can be used to differentiate from other disease related with thyroid gland so as to aid in decision related with its treatment The presence of goiter ,indication of damage of functioning of thyroid gland in tests such as T3,T4 and TSH along with Thyroglobulin test can be used as a crucial tool to determine the presence of any autoimmune disorder related with that of Thyroid gland.
Whenever the immune system of the person attacks the thyroid gland or its proteins it can be fatal as it leads to the chronic inflammation or swelling, damage of the tissues or dysfunction related with the Thyroid gland. The test is crucial monitoring the presence and determination of the amount of Thyroid antibodies specific to Thyroid gland .The butterfly shaped gland known as the Thyroid gland is present in the throat region in the human body. The thyroid gland is responsible for the production of hormones like T3, T4 and Thyroxine which are crucial for regulating the rate of metabolism process within the body. The body is able to regulate the production of thyroid hormones and can maintain a constant amount of it in the bloodstream by the feedback system present in the body any interference of the Thyroid antibodies can result in chronic conditions related and autoimmune disorders associated with disease like the Graves’ disease, Hashimoto Thyroiditis or Hypo/Hyper Thyroids.
To determine the presence of the autoimmune thyroid disorder generally a single or more than one test is done.
The test is summarized as under:
- Thyroperoxidase antibody (TPO)—this test is done to detect the condition of Hashimotos Thyroditis or the disease such as Grave’s disease.
- Thyroglobulin antibody (TGAb)—This acts an indicator as its target is thyroglobulin as it is seen to attack Thyroglobulin which is the storage form of the hormones of the Thyroid gland
- Thyroid stimulating hormone receptor antibodies (TSHRAb)—these are 2 in number and are seen to bind with the receptors in the Thyroid gland basically the TSH receptors.
- Thyroid stimulating immunoglobulin (TSI) this acts by binding itself to the receptors and by promoting the formation of Hormones called thyroid hormones responsible for the condition of Hyperthyroidism.
Thyroid binding inhibitory immunoglobulin (TBII): This antibodies works by blocking the TSH to bind with receptors and in turn leading to the blockage of the thyroid hormones.
The following table summarizes when thyroid autoantibody tests may be done.
TRAb, TSHR Ab, TSI
Graves’s disease -To monitor the effectiveness of anti-thyroid therapy - When a person has symptoms of hyperthyroidism.
Hashimoto thyroiditis; Graves’ disease: - When physician is staring with drug there pay and patient have a related risk of getting hypothyroidism.
Thyroid cancer; Hashimoto thyroiditis - Thyroglobulin test is performed to identify the presence of the antibodies which can interfere with the results.
How is the test done?
This test is done by the healthcare provider by the collection of the blood sample. The sample of blood will be taken from the vein in the arm through the needle and will be collected in the tube .The sample will be then sent for further diagnosis. The result obtained from the lab will help the physician to provide more information about the results to the patient what does it mean.
In young children and infants the use of lancet to puncture the skin for the collection of blood sample is done.
It is seen that Thyroglobulin antibodies bind with the Thyroglobulin antibodies and interferes with the results of the test. The lower levels of Thyroglobulin antibody causes problems
The RIA is used to calculate the bound and unbound Thyroglobulin antibody. So it is seen that .RIA can check the Thyroglobulin level but it is seen that it overestimates the value of Thyroglobulin antibody present in the body of a person. So some physicians recommend the use of RIA during the presence of thyroglobulin antibody.
Some labs use the Thyroglobulin recovers for the determination of the Thyroglobulin antibody if it is causing any interference. By this method a measurement of Thyrglobulin is done and if a reliable amount of it is inspected then it means that the Thyroglobulin antibody has not interfered in the test and the value is reported...On the other hand if the value is not up to the mark then in such case the thyroglobulin antibody is suggested and the value is not reported.
The interference of Thyroglobulin is seen vital and all the assays related with the Thyroglobulin should also include a measurement of the Thyroglobulin antibody.
If the Thyroglobulin antibody is newly detected in patient who have the condition of Thyroid cancer formerly can have its occurrence again.
A rise or persistent thyroglobulin antibody level in the patient having thyroid cancer without the presence of the autoimmune thyroid disease is seen as an indicator of the tumor.
The Thyroglobulin value reported can be higher than unbound thyroglobulin value but the probability of it be false is less.
Due to the difference in the results of RIA and immunometri assay exoerts suggest that the RIA should be used to determine the Thyroglobulin of the serum if the antithyroglobulin antibodies are present with keeping the assumption that the lower value will reflect the correct value and the clinical condition associated with it. RIA approach is authenticated and caution should be kept while interpreting the results but this is not a widely available approach.
This test is mainly done to differentiate between the Thyroid diseases due to autoimmune condition with that of the Thyroid nonfunctioning. Other than that it can also be ordered to identify the cause behind the occurrence of the condition of Goiter or any signs related with the levels of thyroid hormone are its lower or higher level. This testing can be followed when other tests such as T3, T4, and/or TSH are able to determine the nonfunctioning of the Thyroid gland.
More than single thyroid antibody test can also ordered if an individual is detected with some known autoimmune condition which is not related with the thyroid gland like , rheumatoid arthritis, pernicious anemia, systemic lupus erythematosus in which certain symptoms are seen which shows the involvement of the Thyroid gland.
What Are the Risks of the Test?
As such the risk attached with the removal of the blood sample is nil but certain inflammation or pain may or may not rise due to the insertion of the needle stick. Pain/hurt can be experienced near the needle punctured site. After the risk remain general with the routine blood sample test too. Some other things which can happen during or post the blood test are as follows:
- Difficulty in getting the sample due to the less visibility of the vein leading to the insertion of the needle sticks at various places.
- Extreme bleeding can occur at the needle inserted region
- The feeling of fatigue or fainting or headache is likely to occur.
- The condition of Hematoma is seen which is characterized by the accumulation of the blood beneath the skin of the person.
- The chances of getting infection in the area where the needle was inserted.
What are the preparations essential for the test?
The physician will provide all the necessary information which is required to be taken by the patient prior to the test .Generally you will be advised to fast for the day when you will be supposed to do the blood test. The fasting needs the individual not to consume or drink anything for several hours prior to the test if not done the results obtained will not be useful for the further investigation.
Other than that certain medications is seen to alter the results of the test like the Warfarin which is a blood thinner and the physician can ask to stop the intake the consumption of such medication. The medication need to be discontinued for some time till the blood sample is taken.
The physician should be well informed regarding the drugs one is on be it the prescribed/no prescribed ones and the medication should not be stopped until the physician ask to do the same.
The needle insertion during the blood draw can affect some individual and they may experience pain while other may feel like a prick or no sensation at all. After some time itching can be observed in the punctured site.
The process of formation of Thyroid hormones takes place with the help of the protein called Thyroglobulin. There is a possibility that the Thyroglobulin may be attacked by the antibodies of the immune system and can affect the functioning of the Thyroglobulin protein.
What do the results of the test suggest?
The variation is seen the results of the lab test and it varies depending on the factors such age, health history, gender etc. The healthcare practitioner should be contacted if someone has any questions related with the test
The normal results for the adults are:
- The normal values of Enzyme-linked immunosorbent assay is considered <5 International Units/mL
- The values for the Radioimmunoassay is <20 International Units/mL
- The value for the Tanned RBC agglutination is in the ratio 1:10
- The normal value of Indirect immunofluorescence microscopy should be Negative
The negative value depicts the normal value for the Antithyroglobulin antibody test. This shows the absence of antibodies in the blood and it is present in lesser amounts it can suggest the presence of certain problems related with the health of the person which can be related to following conditions summarized as under:
- Presence of cancer of the Thyroid gland
- Presence of the Diabetes (Type 1) called as the Diabetes mellitus.
- Certain conditions such as rheumatoid arthritis where the immune system attacks the joints of the person.
- Pernicious anemia, which takes place due to the reduced level of RBC which is caused by the deficiency of Vitamin B12.
- Certain disease like the Collagen vascular disease.
If the levels of the antibody in the blood are seen higher it indicates the person is suffering from the autoimmune disorders such as
- Graves’ disease
- Hashimoto thyroiditis
It is seen that antithyroglobulin antibodies is suggestive of the severe health related problems and there are situation in which these antibodies are seen without having any complications attached with it. Antithyroglobulin antibodies have been found to increase in women as they age, but without any corresponding health problems. It is seen that the antithyroglobulin antibodies rises with increasing age in the women but no problems related with health is seen.
If the antibodies are present in the human body without any particular reason behind the same the physician can observe the health and the levels of the antibody so that no severe problems occur.
A negative test is considered as a normal value and suggests that antibodies to Thyroglobulin are not present in the blood.
Normal values vary from lab to lab. Some labs use different sample measurement. Your physician should be well informed regarding the specific test results:
A positive test indicates Antithyroglobulin antibodies are present in the serum/blood of a person and this can be due to reasons such as:
- Disease such as Graves’ disease.
- Myxedema(A disease caused by decreased activity of the thyroid gland in adults and characterized by dry skin)
- Hashimoto's thyroiditis (Inflammation of the thyroid gland.)
- Systemic lupus erythematosus
- Type 1 diabetes(Diabetes Mellitus)
A positive test means antithyroglobulin antibodies are found in your blood. This may be due to:
Certain conditions such as pregnant women relatives suffering from autoimmune thyroiditis may also test positive for these antibodies.
The Negative results of the test suggest that absence of the autoantibodies in the bloodstream during the test and may also indicate other causes than the autoimmune cause. But certain population of people who have the Thyroid disease which is autoimmune type, the autoantibodies seize to exist. If it is likely that the autoantibodies develop over time which is likely in certain autoimmune disorders, then frequent testing may be done after some time. The mild to moderate levels of thyroid antibodies is found in certain thyroid and autoimmune disorders like the cancer of the Thyroid gland Type 1 diabetes (Diabetes Mellitus), rheumatoid arthritis autoimmune collagen vascular diseases.
Increased or higher concentrations frequently indicate the disease related with thyroid autoimmune diseases like that of Hashimoto thyroiditis Graves’ disease.
The occurrence of Thyroid antibodies generally indicate a corresponding involvement of the Thyroid gland and the higher the autoantibodies the more severe the condition is. . Rising levels may be more important as compared with the normal levels as it suggest there is rise in the autoimmune activity. If these antibodies occur in the pregnant woman, the risk of occurrence of hypothyroidism or hyperthyroidism rises in the baby.
Presence of thyroglobulin antibodies while the physician is observing the thyroglobulin levels, it is likely to interfere with the results of the test. This suggests that the physician is less likely to use Thyroglobulin as an indicator for the cancer related with the thyroid gland. If thyroglobulins antibodies used as a measuring factor and remained higher or low during the initial period but start rising over the period of time then it indicates that the treatment of it was not fruitful or effective and that the condition still remains or occurring again. An efficient/justifiable therapy is seen when the level of the antibodies fall to lower or nondetectable levels.
It is seen that certain percentage of healthy individual too can be positive for 1or more than one thyroid antibodies. The occurrence of these antibodies rises with age and also in women and suggests the rising risks of developing certain disease related with Thyroid gland afterwards in the future. A person suffering from no malfunctioning of the thyroid gland but the presence of thyroid antibody detected then the physician will monitor and keep a track of the health of the person over some time.
The sensitive and specific nature of thyroid antibody testing is no doubt getting better day by day but still it has not reached the level where the physician expect or would like it to be. Almost every test related with the thyroid antibody has changed over the period of time and has been called by different names with the changing times. There are different methods of its determination and each method has different range.