Lupus is notoriously difficult to diagnose. That’s because the common symptoms can be quite different from person to person, and symptoms like pain cannot be measured by laboratory tests. Plus, there is no one lab test that can be used to definitely diagnose lupus.
Doctors must look at a combination of test results plus the signs they can see when you are in their office. Your doctor may have to run a series of tests over time and watch the results before making a firm diagnosis of lupus. This is because many of the biomarkers tested are negative or normal early in the course of the disease.
The most common tests for lupus fall into 4 categories – blood work, urinalysis, biopsy, and imaging. Your doctor may run some or all of these tests, sometimes several times, to diagnose and monitor lupus or to rule out other conditions.1-2
Blood tests
Blood tests can reveal signs of inflammation in the body that your doctor cannot see yet. These tests can also measure how well your blood is clotting, whether you are anemic, and how well your kidneys are working. There are several blood tests your doctor may run include:1-2
- Antinuclear antibody (ANA) test
- Complete blood count (CBC)
- Comprehensive metabolic panel
- Immunologic tests
- Direct Coombs test
- Serum creatinine test
After someone is diagnosed with lupus, many of these tests are also used to monitor different antibody levels in the body over time.
Urinalysis
Urinalysis is used to decide if lupus may be attacking your kidneys or if you already have a type of kidney damage called kidney nephritis.
A urine test will measure levels of protein, red blood cells and white blood cells in your urine. Too much protein in the urine can be a sign of inflammation in the kidneys. If the protein levels in your first urinalysis are high, your doctor may follow up with a 24-hour urine sample or a protein-to-creatinine ratio test to get a clearer picture of how well your kidneys are working.1-2
Too many red blood cells in the urine also point to kidney inflammation or damage. Too many white blood cells may signal either a bladder infection or inflammation of the kidneys.
Biopsy
A biopsy is a test where the doctor takes a small tissue sample to look for signs of inflammation. Skin and kidney are the most common types of biopsies done when your doctor suspects lupus. A skin biopsy may help rule out other types of skin disorders. A kidney biopsy is performed less often because it is invasive (requires surgery). It is used to confirm kidney damage.1-2
Imaging
Imaging tests can reveal signs of internal damage that the inflammation lupus causes to the joints, kidneys, heart, lungs and other major organs. Imaging tests for lupus can include:1-2
- Chest x-ray
- X-ray of joints
- Echocardiogram
- MRI (magnetic resonance imaging)
These tests can reveal signs of inflammation or damage to the heart, lungs, and brain. X-rays of painful, swollen joints can be used to diagnose and monitor joint damage, which is called arthritis.
If you are diagnosed with lupus, your doctor will order many of these same tests to track how active your lupus is, how well your medicines are working, and the progression of the disease.
Early diagnosis is important
Lupus is a chronic, progressive disease, so early diagnosis helps slow or even stop the damage it does to your joints, kidneys, and other organs. While there is no cure for lupus, many treatments are available to help reduce serious complications and improve your quality of life.