Every cell and tissue in your body needs thyroid hormone to function properly. Your thyroid works like a thermostat to control how your body uses energy. Too much and your body overheats. Too little and your body becomes sluggish and slow. About 20 million Americans have some type of thyroid disorder, according to the American Thyroid Association. And most don’t know it. Undiagnosed thyroid disorders increase your risk of heart disease, osteoporosis, and infertility. The good news is thyroid disorders are usually manageable. And getting a diagnosis is the first step toward thyroid health. Doctors want to know about your symptoms and will examine your thyroid. You’ve probably had a doctor feel your neck and ask you to swallow. That’s a technique to physically examine your thyroid gland. Doctors feel for the size of the thyroid gland and for any lumps or bumps. Your doctor also needs to know about symptoms you are experiencing. This may include weight loss or gain, intolerance to cold or heat, fatigue, excessive sweating, or even feeling like your heart is racing. Doctors check thyroid function with blood tests. There are sensitive blood tests your doctor can order to check your thyroid function. They include TSH, T4, T3, TSI and TPOab. TSH, T4 and T3 are hormone level tests. These tests accurately show your doctor how your thyroid is working and responding to your body’s needs. TSI and TPOab are tests of your immune system. They help your doctor understand what could be causing your thyroid disorder. TSI is an immunoglobulin test. It can show if your immune system is mistakenly stimulating your thyroid gland. TPOab is an antithyroid antibody test. This test can show if you have antibodies that are mistakenly attacking your thyroid gland. Doctors use imaging exams to find the cause of thyroid disorders. There are several imaging exams doctors use to diagnose and find the cause of thyroid disorders. The first is painless, noninvasive ultrasound. An ultrasound shows the size and texture of the thyroid. It can detect cysts and tumors. Your doctor can also look for patterns of inflammation that may be a clue to the cause. Other imaging exams include CTs and MRIs. But ultrasound is usually the imaging exam of choice for thyroid problems. Doctors can also use a nuclear medicine exam with a radioactive chemical. The thyroid takes up iodine. By using radioactive iodine, doctors can see how much of it your thyroid is using. Doctors may perform a thyroid biopsy if they find a nodule or tumor. The type of biopsy is a fine-needle aspiration. It uses a needle to remove thyroid cells and look at them under a microscope. This tells your doctor if the nodule is benign or cancerous. Once your doctor diagnoses a thyroid disorder and its cause, you can begin treatment and your road to health. Most thyroid disorders are lifelong conditions. But it’s also true that medicines can control the majority of them.