Lupus is an autoimmune disease that affects approximately 1.5 million Americans. It primarily affects the organs, such as the brain, skin, kidneys, and joints. Its symptoms often masquerade as signs of other illnesses, so the condition can be difficult to diagnose. It is good to know the symptoms and diagnosis procedures for lupus so that you can be prepared. You should also know the causes so that you can avoid potential triggers.
1Prepare for your appointment with the doctor. You can go to any general physician for a lupus diagnosis, but that doctor may refer you to a rheumatologist who may order more confirmatory tests and help manage symptoms with specific medication for lupus. Typically, though, the start of a professional medical diagnosis will be at a standard physician’s office.
- Before your appointment, write down information about when your symptoms began and how frequent they are. Also make a note of any medications and supplements you take as possible triggers.
- If a parent or sibling has ever had lupus or another autoimmune disorder, you should bring that information with you as well. Patient and family history are very important for diagnosing lupus.
2Prepare for an antinuclear antibody (ANA) test. ANA is an antibody that attacks proteins in the body, and these ANA are present in most people with an active form of lupus. This is often used as an initial screening test; however, not everyone with a positive ANA test has lupus. Further tests are needed to confirm the presence of lupus.
- For example, a positive ANA test can also indicate scleroderma, Sjogren’s syndrome, and other autoimmune diseases.
3Get a complete blood count. This blood test measures the amount of red blood cells, white blood cells, platelets, and hemoglobin in your blood. Certain abnormalities can be another possible sign of lupus. For example, this test can reveal anemia, which is a common symptom of lupus.
- Note that this test does not diagnose lupus by itself. Many other conditions can also cause similar abnormalities.
4Expect blood tests for inflammation. Your doctor may do several tests that confirm an inflammatory condition, though they will not definitively prove you have lupus. One such test measures your erythrocyte sedimentation rate (ESR). This test measures how fast it takes red blood cells to settle at the bottom of a test tube in one hour. A fast rate can indicate lupus. A fast rate can also be symptomatic of other inflammatory conditions, cancers, and infections, so it is not an absolute test, either.
- Another test that is non-specific for lupus but can test for inflammation is a C-reactive protein (CRP) test. This liver protein can indicate the presence of inflammation, but there are many other conditions that can cause this protein to show up.
5Find out about other blood tests. Since no blood test is exclusive to lupus, doctors usually perform a range of blood tests to narrow down the diagnosis. Symptoms usually must match at least four out of the main eleven symptoms that doctors look for.Other possible tests your doctor might use include:
- A blood test measuring your erythrocyte sedimentation rate. This test measures how fast it takes red blood cells to settle at the bottom of a test tube in one hour. A fast rate can indicate lupus. A fast rate can also be symptomatic of other inflammatory conditions, cancers, and infections, so it is not an absolute test, either.
- An antibodies to phospholipids (APL ) test. An APL test looks for antibodies that attack phospholipids, and they tend to be present in 30 percent of patients with lupus.
- An antibodies to Sm test. This antibody attacks the Sm protein in the cell nucleus, and it is present in about 30 to 40 percent of lupus patients. Moreover, it rarely shows up in people without lupus, so a positive result almost always guarantees a lupus diagnosis.
- An anti-dsDNA test. Anti-dsDNA is a protein that attacks double-stranded DNA. Roughly 50 percent of lupus patients have this protein in their blood. It is very rare in people without lupus, so a positive result almost always results in a lupus diagnosis.
- Anti-Ro (SS-A) and Anti-La (SS-B) tests. These antibodies attack the RNA proteins in your blood. It is more common in patients with Sjögren’s syndrome, however.
6Get a urine test. Urine tests monitor the kidneys, and damaged kidneys can be a sign of lupus. You might be required to provide a urine sample so that the doctor can do a urinalysis. This test looks at your urine for extra proteins or the presence of red blood cells.
7Ask about imaging tests. Your doctor might order an imaging test if they think that you have a form of lupus that affects your lungs or heart. A traditional chest x-ray might be ordered to look at your lungs. An echocardiogram will look at your heart.
- A chest x-ray can reveal shadows in your lungs, which could indicate areas of fluid or inflammation.
- An echocardiogram uses sound waves to measure the beating of your heart and to detect possible problems in the heart.
8Inquire about a biopsy. If your doctor suspects that lupus has damaged your kidneys, they may do a kidney biopsy. The goal of this biopsy is to obtain a sample of kidney tissue. They will assess the condition of your kidneys based on how much damage has occurred, and what kind of damage it is. Doctors can use this biopsy to determine the best treatment for lupus