The path to a systemic lupus erythematosus (SLE or lupus) diagnosis can be a long and uncertain one. It takes six years on average to receive a definitive diagnosis after symptom onset. It can be difficult for healthcare professionals to identify exactly what’s causing your symptoms because lupus can look like other health conditions. Sixty-three percent of people ultimately diagnosed with lupus will first receive at least one misdiagnosis.

One MyLupusTeam member recalled, “I was always sick as a child. In my thirties, my doctor sent me to a specialist who determined I didn’t have lupus. It was diagnosed when I was 58.” Another member said, “I was diagnosed at 64. I had fibromyalgia for 20 years; they now think it may have been lupus.”

What Are the Criteria for a Lupus Diagnosis?

There isn’t one single test to prove lupus. The European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) have developed a diagnostic algorithm as a guide to diagnose lupus. This algorithm helps narrow down a diagnosis based on symptoms and test results. Researchers group these findings into clinical (signs and symptoms) and paraclinical (lab results and imaging findings) categories based on the organ or body system that’s affected and assign them a weighted score. To apply the algorithm, a physician must see if the patient fulfills the entry criterion, represented by a positive antinuclear antibody (ANA) test result (a type of blood test). To meet the criteria, the clinical and paraclinical findings must add up to at least 10 points.

Sometimes, someone has symptoms of lupus, but they do not meet the criteria for diagnosis. In these cases, the doctor may consider a diagnosis of borderline or incomplete lupus and repeat testing later to see if the score has changed.

Who Should Be Tested for Lupus?

Your doctor may consider testing for lupus if you have the following common symptoms:

• Skin rashes, such as a “butterfly rash”
• Joint pain or swelling
• Mouth or nose sores
• Bruising easily or abnormal bleeding
• Brittle hair or hair loss
• Raynaud’s phenomenon, a color change — red, white, or blue — in the fingers when exposed to cold
• Blood in urine, foamy urine, or frequent urination
• Inflammation in the heart or lungs
• Neurological problems such as seizures or strokes
• Tiredness

It’s possible to have lupus without having any signs or symptoms on this list, or only having one or two. In this case, the doctor may wait to see whether other symptoms appear before performing more testing.

If your doctor suspects lupus, they’ll likely perform tests to help confirm or rule out the diagnosis.

How Do Healthcare Professionals Test for Lupus?

Some tests can provide proof of lupus-like inflammation. Others rule out different conditions. Again, no one test provides absolute confirmation of lupus, but there are some antibodies that are specific for lupus, and with other common findings, they can strongly suggest the diagnosis.

Medical History

Your rheumatologist will take a thorough history, asking questions about:

• Symptoms over time
• Family medical history
• Possible exposures to toxins or infections

A clear picture may emerge from the medical history. With this information, a doctor can assess risk factors that may strengthen the suspicion of lupus or rule out other conditions.

Blood Tests

Your doctor will order multiple blood tests to assist with the diagnosis of lupus. Among the most important are complete blood count (CBC), complement, antibodies, and the Coombs test.

Antibodies

Antibodies are proteins produced by the immune system. These proteins mark and neutralize invading substances such as bacteria and viruses. In people with autoimmune diseases, the body produces autoantibodies. These antibodies attack the body’s tissues. An autoimmune panel — often performed on one blood sample — detects the presence of these antibodies in the blood.

A positive ANA result is a mandatory criterion for a lupus diagnosis. Other antibodies that may appear in blood work for a person with lupus include:

• Anti-cardiolipin antibodies
• Anti-beta 2 GP1 antibodies
• Lupus anticoagulants

Lupus-specific antibodies include anti-dsDNA and anti-Smith (anti-Sm) antibodies. The presence of one of these antibodies increases suspicion for lupus.

Proteins

Your blood can also be analyzed for proteins, specifically C3 and C4. Low levels of these proteins indicate inflammation and any problems with liver or kidney function.

Blood Counts

A complete blood count can show whether you have low red or white blood cell counts or low platelets. Lupus and other conditions can cause low counts of any type of cell.

If your red blood cell counts are low, your doctor may order additional testing on the blood to rule out a condition called hemolytic anemia. This autoimmune destruction of red blood cells is sometimes associated with lupus.

Other Blood Tests

Your doctor may also test how well your blood clots. Some people with lupus have abnormal blood clotting.

Other Diagnostic Tests for Lupus

Diagnostic tests help determine a lupus diagnosis.

Urinalysis

Healthy kidneys filter out all protein and cells. If there are proteins or red blood cells in the urine, it can indicate kidney damage. An abnormal urine test result may suggest lupus nephritis, or inflammation in the kidneys.

Imaging

The doctor may order a chest X-ray to check for fluid or inflammation in the lungs and an abdominal ultrasound to check for fluid in the abdomen. An echocardiogram will show any abnormalities in the way the heart is beating, and a cardiac ultrasound will show any functional abnormalities and is useful to check for fluid in the heart.

Biopsy

During a biopsy, a doctor takes a small tissue sample for lab testing. The doctor may take a biopsy of the skin or kidney if they suspect lupus.

Neurological Exam

If you’ve experienced symptoms like “brain fog,” sleeplessness, or headaches, your doctor may perform a neurological exam.

During this specialized exam, the doctor will check for:

• Signs of nerve damage by examining your eyes and reflexes
• Weakness or lack of coordination by having you move your arms and legs in specific ways
• Loss of sensation by touching various parts of your body with a vibrating tuning fork or sharp or dull items

The neurological exam provides an objective assessment of signs and symptoms that may suggest lupus or another condition.

What Confirms a Lupus Diagnosis?

To confirm a diagnosis of lupus, your doctor must rule out other causes for your symptoms. Several conditions can produce lupus-like symptoms. For this reason, lupus is sometimes referred to as “the great imitator.” Differential diagnosis is the process of ruling out similar conditions. To list a few, conditions that may resemble lupus may include:

• Fibromyalgia
• Rheumatoid arthritis
• Hashimoto’s disease
• Sjögren’s syndrome

Your doctor may be able to rule out many of these conditions based on your medical or family history or blood tests. Other disorders may require time and repeated tests before being confirmed or ruled out. It’s possible to have other diseases in addition to lupus, which complicates the differential diagnosis. Having more than one disease also eventually results in multiple diagnoses.

After obtaining the necessary results, your doctor can use this information to confirm a diagnosis of lupus.

Talk With Others Who Understand

On MyLupusTeam, the social network for people with lupus and their loved ones, members come together to ask questions, give advice, and share stories with others who understand life with lupus.

Did your path to a lupus diagnosis include numerous tests or misdiagnoses? Are you still waiting for an official diagnosis? Share your experience in the comments below, or start a conversation by posting on MyLupusTeam.