context: Lyme disease can be tricky to diagnose. The signs and symptoms can look like many other health problems. The ticks that spread it can pass other diseases on to you at the same time. Plus, the tests that check for it aren't exact. Because of this, you could be told you have Lyme disease when you don't. This bacterial infection is spread through the bite of a young deer tick or black-legged tick. These eight-legged creatures, about the size of a poppy seed, can be found in wooded and grassy areas throughout the United States, especially in New England and the Rocky Mountains. Because these ticks are so small, most people don't realize when they're bitten. But the longer a tick stays attached to you, the more likely it is to transmit Borrelia burgdorferi (the bacteria that causes Lyme disease), if the tick is a carrier. If not found and treated, Lyme disease can lead to problems with your joints, heart, and nervous system. It can even affect your memory. If you've been outside in an area where ticks are known to live, you should tell your doctor. She'll also want to know about the symptoms you're having. These details are crucial to making a diagnosis of Lyme disease. Early symptoms that usually occur within the first month after a tick bite can include: Rash at the site of the tick bite that may look like a âbull's-eyeâ Headaches Fever Muscle aches Fatigue Symptoms that show up in the weeks to months after a tick bite include: Dizziness Nerve pain Shortness of breath Additional rashes on other parts of the body Facial palsy ( Drooping or loss of muscle tone in your face) Tingling in the hands and feet Severe joint pain or swelling Racing heart Problems with your short-term memory Symptoms that come and go are common with Lyme disease. They will also depend on the stage of the disease. If your doctor suspects that you have Lyme disease, she may order two blood tests. These will look for signs that your body is trying to fight it off. The results are most precise a few weeks after you've been infected. These tests are: ELISA (enzyme-linked immunosorbent assay) test. This test can't check for the bacteria that causes Lyme disease. It can only look for your immune system's response to it. Once Borrelia burgdorferi gets into your blood, your body begins to make special proteins called antibodies to fight it off. The ELISA test checks for those antibodies. Although it's the most common way to check for Lyme disease, the ELISA test isn't perfect. It can sometimes give false âpositiveâ results. On the other hand, if you have it done too soon after you've been infected, your body may not have developed enough antibodies for the test to detect them. This will give you a ânegativeâ result even though you do have Lyme disease. Western blot test. Whether your ELISA test comes back positive or negative, your doctor will need to do this blood test, too. A Western blot uses electricity to split certain proteins in your blood into patterns. This is then compared to the pattern of people known to have Lyme disease. At least five band matches means that you have Lyme disease. Still, not all labs have the same standards. There's a chance that you could get a âpositiveâ result from one and a ânegativeâ result from another. Also, some labs offer a test for Lyme disease using your urine or other body fluids. These methods aren't approved by the FDA. Studies also show that the results often aren't correct. You may be told that you have Lyme disease when you don't. Other tests: Lyme disease is called â The Great Imitatorâ because it mimics so many different health conditions. Your doctor may also want to do more blood or imaging tests to rule out: Alzheimer's disease Arthritis Attention deficit disorder Chronic fatigue syndrome Fibromyalgia Guillain- Barre syndrome Lou Gehrig's disease ( ALS) Lupus Mononucleosis Multiple sclerosis Parkinson's disease If you think you have Lyme disease, it's a good idea to see a board-certified infectious disease specialist. This type of doctor is skilled in both diagnosis and treatment. The tests that look for Lyme disease aren't foolproof, so your doctor may decide to start you on treatment based on your symptoms and the likelihood you've been exposed to ticks. Ideally, the diagnosis will be confirmed for treatment to continue.