Lab Tests for Lupus

Many different lab tests are used to find changes in your body that can happen with lupus. The results of each test help your doctor get a fuller picture of your health. 

Because lab tests alone can’t diagnose lupus, your doctor will also consider other signs and symptoms of the disease when making — or ruling out — a diagnosis. Learn more about how lupus is diagnosed. 

Common tests for diagnosing lupus

The most common types of tests for diagnosing lupus are blood and urine tests. In some cases, a tissue sample (biopsy) may also be used.

Blood tests

Common blood tests for lupus include:

Complete blood count (CBC) 

A CBC is a routine test that measures your levels of:

• Red blood cells, or hemoglobin, which carry oxygen through your body
• White blood cells, which help the immune system protect the body
• Platelets, which form in bone marrow and help the blood clot when it needs to

In lupus, these levels may be low.

Antibody tests

Antibodies are what your body uses to attack things that can harm it, such as bacteria and viruses. But in lupus, your body makes antibodies, called autoantibodies, that attack its own normal cells. Many of those antibodies can be found on a panel (a group of tests ordered at the same time). Doctors trying to diagnose lupus can look for several different types of antibodies.

The test you’ll hear about the most is called the antinuclear antibodies (ANA) test. This test isn’t a specific test for lupus — it can be positive in people with other illness or without an illness. So having a positive ANA test doesn’t always mean you have lupus. But when the test is positive, and you also have several other signs of lupus that doctors look for, it’s a strong signal for your doctor to consider lupus. 

97% of people with lupus will test positive for ANA

Other blood tests

Some blood tests measure levels of proteins that aren’t antibodies such as c-reactive protein and complement levels. The levels of these proteins can alert your doctor that there’s inflammation somewhere in your body. 

View our Glossary of lupus blood tests for more details.

Urine tests

Urine tests can help your doctor see how well your kidneys are working. Lupus can attack the kidneys suddenly, and urine tests are important because they can help find signs of a problem. 

The most common urine tests look for protein or bits of cells (called cell casts) in the urine that would normally be filtered out by kidneys that are working well. Most urine tests can be done on one sample of urine. But in some cases — when more information is needed — you’ll need to collect samples over 24 hours.

Tissue biopsies

A biopsy is a sample of tissue that can be examined under a microscope. The most common types of biopsies in people who may have lupus are skin and kidney biopsies.

Tissue samples of skin are done by using a hollow needle to remove a small piece of skin. Tissue samples from the kidneys are done using a needle and an ultrasound to guide it.

The tissue sample is examined for signs of inflammation or damage. Further  tests on the sample can check for ANA, and find out whether lupus, an infection, or medication is causing ANA to develop.