The TPO (thyroid peroxidase antibody) blood test is designed to help a medical provider determine whether or not there may be an autoimmune thyroid disease present. This test helps to distinguish the autoimmune disorder from other forms of dysfunction that may occur. When an individual’s immune system targets the thyroid gland in some way mistakenly, antibodies that are specific to those components appear in the blood. This test will determine if they are present.
There are several blood tests that can be ordered to determine if there are thyroid-related autoimmune antibodies that are present in the blood. The TPO blood test is the most common of these tests as it can help to detect the presence of Hashimoto thyroiditis or Graves disease.
When Will the TPO Blood Test Be Ordered?
The most common reason why the TPO blood test is ordered by a medical provider is because there is the presence of a goiter. This simply means that the thyroid has become enlarged in some way. There may also be the signs and symptoms of having too much or too little thyroid hormone present within the blood. This could be due to an inflammation or infection that has occurred near the thyroid or if an impact injury has damaged the tissues of the thyroid in some way.
If someone has too little thyroid hormone, then they may experience fatigue, hair loss, constipation, and weight gain. There may also be abnormal amounts of dry skin noticed and difficulty in dealing with cold temperatures. These symptoms may be chronic or acute and vary in severity.
If someone has too much thyroid hormone, then a rapid heartbeat and sweating are the most common symptoms noticed. There also tends to be an increased level of anxiety, muscle tremors, and problems sleeping. Some individuals may notice fatigue despite getting enough sleep every night and experience weight loss without dieting. Eyes that protrude is a common tell of having too much hormone present in the blood.
What Do My Test Results Mean?
TPO blood test results are typically communicated as being positive or negative. If it is negative, then this most likely means that there are no antibodies present in the blood at the time the test was conducted. If there are bothersome symptoms present, then it indicates that the cause may be something other than an autoimmune disorder. A negative result doesn’t 100% exclude an autoimmune issue, however, because a certain number of people who have an autoimmune thyroid disease don’t develop antibodies.
A positive test result indicates that there is an autoimmune issue that is present. The level of severity in the positive result indicates what type of disorder a person may be facing. Low to moderate increases in thyroid antibodies can indicate the presence of rheumatoid arthritis, diabetes, and anemia. It can also indicate thyroid cancer in addition to an autoimmune disorder. Severely high positive test results are usually an indication that Hashimoto thyroiditis or Graves disease is present.
In basic terms, the higher the levels of TPO that are discovered in the blood, the more severe the autoimmune condition will be. If found in women who are pregnant, then the results can be a reflection of what a newborn may face later on in life.
Here’s What You Need To Know
There is a specific percentage of the population that will test positive on the TPO blood test despite being completely healthy. This tends to happen more often in women and the chances of this happening increase with age. This is typically treated as an increased risk for developing an autoimmune thyroid disorder in the future, but ultimately depends on an individual’s medical history. Most people who fit into this category do not experience thyroid dysfunction.
The sensitivity of the TPO blood test is not considered to be as good as it could be. The blood tests have been changing over time to take advantage of improved testing methods, but the specificity of the test makes it difficult to be used on its own to create a diagnosis. For this reason, it is very common for a medical provider to request a complete thyroid panel when the TPO test is needed.
This is not a routine blood test. It is only ordered if there is a suspected autoimmune thyroid issue. For specific questions about your test results, be sure to speak with your medical provider. Only your doctor can interpret what your results may mean for your medical history.