Lupus (systemic lupus erythematosus, or SLE) can be hard to recognize, sometimes taking weeks to years to diagnose. Lupus affects different people in different ways, and it can take time to develop the symptoms that suggest this disease. Your health professional will record your medical history and perform a physical examination, checking for the presence of certain criteria to help diagnose lupus. These criteria are used to separate lupus from other similar diseases. A person with 4 of these 11 conditions can be classified as having lupus. These conditions may be present all at once, or they may appear in succession over a period of time.¹

Classification criteria for systemic lupus erythematosus:

• Butterfly (malar) rash on cheeks
• Rash on face, arms, neck, torso (discoid rash)
• Skin rashes that result from exposure to sunlight or ultraviolet light (photosensitivity)
• Mouth or nasal sores (ulcers), usually painless
• Joint swelling, stiffness, pain involving two or more joints (arthritis)
• Inflammation of the membranes surrounding the lungs (pleuritis) or heart (pericarditis)
• Abnormalities in urine, such as increased protein in the urine or clumps of red blood cells or kidney cells, called cell casts, in the urine
• Nervous system problems, such as seizures or psychosis, without known cause
• Problems with the blood, such as reduced numbers of red blood cells (anemia), platelets, or white blood cells
• Laboratory tests indicating increased autoimmune activity (antibodies against normal tissue)
• Positive antinuclear antibody (ANA) test

Initial diagnosis and disease monitoring

If you have physical signs of lupus and a positive ANA test result, further testing may not be necessary. If your doctor feels that further testing is necessary to clarify your diagnosis, you may have one or more of the following tests:

• Other antibody blood tests
• Complement test
• Erythrocyte sedimentation rate (ESR, or sed rate) or C-reactive protein (CRP)
• Complete blood count (CBC)
• Urinalysis

Evaluating possible organ damage

As part of ongoing treatment for lupus, you may have a:

• Urinalysis to check for protein and cells, signs of possible kidney problems.
• Kidney biopsy, if your doctor sees signs of kidney inflammation. This test may help your doctor determine the best treatment for you. Only a small number of people with lupus need a kidney biopsy.

To evaluate other possible causes of symptoms, imaging tests are sometimes done, depending on which organ systems are involved. Imaging tests include computed tomography (CT) scan, echocardiogram, magnetic resonance imaging (MRI), and X-rays.