Lab Testing for Lupus

Lupus refers to a chronic inflammatory autoimmune disorder.  This means it impacts the immune system by causing an excessive immune response against the body’s own tissues. In general, the immune system is designed to protect the body from external toxins and/or infections, but lupus causes the system to turn on its own body.  This causes the immune system to go after the blood vessels, joints, skin, and internal organs such as the lungs, brain, kidneys, and heart. It’s important to note there are several types of lupus; however, the most common is systemic lupus erythematosus (or SLE), and it affects a significant portion of the human body. 

Lupus and its symptoms can occur at any age but are most common in women of child-bearing age.  It is also far more common among women than men by a ratio of 10:1. In terms of a person’s ancestry, those coming from African, Hispanic, Asian, and Native American descent are most likely to be diagnosed with lupus.  With systemic lupus erythematosus, people between the ages of 15 and 44 are most prone to being diagnosed with it, but the condition is also seen in newborns and older adults. 

The root cause of lupus is still to be determined.  However, medical professionals and researchers state it likely involves a genetic component along with a personal trigger, which can vary from person to person, such as exposure to sunlight, viral infections, and/or specific prescription medications.  Lupus is also known to co-exist with other autoimmune disorders such as Hashimoto thyroiditis, hemolytic anemia, Sjögren syndrome, and idiopathic thrombocytopenic purpura (or ITP).  

There are multiple types of lupus, and here are the most common ones:

  • Systemic lupus erythematosus (or SLE) – This is the most common type of lupus and is noted for beginning with a subtle selection of signs/symptoms.  The Centers for Disease Control and Prevention states that approximately 16,000 new cases of SLE pop up in America each year, while 1.5 million Americans live with the condition. From the 1.5 million Americas that are already living with lupus, 90% of these cases involve women of child-bearing age.  SLE is known for targeting various parts of the human body at a systemic level. 
  • Discoid lupus – This is a type of lupus that is known for the development of chronic skin rashes. This rash tends to spread along the face and/or scalp.  Discoid lupus carries a 15-20% chance of turning into SLE.  
  • Subacute cutaneous lupus – This is a type of lupus that brings along with it skin lesions that are spread across multiple parts of the body subject to sun exposure. 
  • Drug-induced lupus – This is a type of lupus that is triggered through the use of specific drugs, which can include high blood pressure, anti-seizure, and anti-thyroid medications.  The particular medications include hydralazine (treatment for hypertension), procainamide (treatment of abnormal heartbeat patterns), and antibiotic isoniazid (treatment for tuberculosis).  With this type of lupus, the patient develops various symptoms a few months after the drug has established itself in the system.  However, these symptoms can go away once the medication has been stopped. 
  • Neonatal Lupus – This is a type of less common lupus that affects newborn babies leading to a set of symptoms such as liver problems, skin rash, and low blood cell counts.  These symptoms take a few months to go away, and, in many cases, a newborn has lupus because their mother already has SLE or Sjögren syndrome.  However, a newborn baby can be diagnosed with neonatal lupus even if their mother hasn’t been diagnosed with any form of lupus.  Other autoantibodies can simply trigger it in a mother’s bloodstream, such as anti-SSB/anti-SSA, which impact the fetus.  This is why women have to be monitored more closely when it comes to the presence of these autoantibodies during pregnancy. 

Signs and Symptoms 

There are several signs and symptoms associated with lupus, and they can vary in each patient. 

Patients dealing with lupus can develop rashes such as: 

  • An oval-shaped or a round rash that’s red (a discoid rash) 
  • A butterfly-shaped rash that spreads across the face (a malar rash) 
  • A rash spread across different body parts subject to sun exposure (i.e., face, arms, legs) 

Often in people with subacute cutaneous lupus and discoid lupus, a rash is the only symptom.  

Individuals with other types of lupus may present a combination of these signs or symptoms: 

  • Fever 
  • Muscle pain 
  • Continuing fatigue  
  • Chest pain 
  • Hair loss 
  • Fingers changing color following stress or exposure to cold (Raynaud phenomenon) 
  • Arthritis 
  • Swollen lymph nodes 
  • Anemia 
  • Joint pain like with arthritis but with no or little damage to the joint 
  • Sensitivity to sunlight 
  • Mouth ulcers 
  • Organ damage or inflammation (i.e., lungs, heart, central nervous system, kidneys, lining of the heart, and/or blood vessels) 

These symptoms can vary both in consistency and intensity, depending on the individual.  In some cases, a person may see an extreme bout of symptoms for a few months before seeing them taper off for a bit.  The return of these chronic symptoms can vary with flare-ups becoming an issue depending on specific triggers such as a person’s health, stress levels, external exposure (i.e., sunlight), pregnancies, or birth. 

A person that is dealing with lupus can also become prone to developing infections. These can include infections such as UTIs (or urinary tract infections), yeast infections, herpes, shingles, respiratory infections, and salmonella because their immune system isn’t running in top gear all the time. This can also lead to additional concerns about tissue death, miscarriages, and pre-eclampsia.  

Tests and Diagnosis 

The diagnostic process behind lupus can be difficult at the best of times due to the extensive list of symptoms. These symptoms also come and go making it difficult to come up with a comprehensive evaluation of the patient and their condition. Certain tests can be run to rule out other causes based on the symptoms that are present. 

The American College of Rheumatology took the time to develop classification criteria to assist physicians during the early-80s. These criteria were designed to assist with diagnosing SLE as it is the most common type of lupus; however, the criteria were updated against during the late-90s.  

These criteria include the following symptoms.  A person exhibiting at least 4 of the 11 following signs or symptoms may be diagnosed as having lupus:  

  • An oval-shaped or a round-shaped rash that is red (a discoid rash) 
  • A butterfly-shaped rash spread across the face (a malar rash) 
  • Mouth sores and/or nose ulcers 
  • Photosensitivity (consistent development of rashes on body parts exposed to sunlight (face, arms, legs, hands) 
  • Arthritis across multiple joints including tenderness, swelling, and/or accumulation of fluid in the joints; SLE-associated arthritis is non-erosive, so the bones near the affected joints are not damaged 
  • Kidney issues – elevated protein levels within the urine and/or cellular cysts 
  • Hematologic (blood) disorder – low white blood cell count, anemia, or low platelet count 
  • Pericarditis (inflammation of the lining around the heart) or pleuritis (inflammation of the lining around the lungs) 
  • Neurologic disorder – psychosis and/or seizures without relevant causes 
  • Positive blood test (antinuclear antibodies) – high levels can indicate SLE or drug-induced lupus (assuming specific medications were consumed) 
  • Positive blood test (anti-double-stranded DNA, cardiolipin antibody, anti-Sm (Smith) antibody, or lupus anticoagulant) or a false-positive test for syphilis (i.e., the person tests positive but doesn’t actually have the disease)  

It was in 2012 when the Systemic Lupus International Collaborating Clinics group took the time to verify the ACR’s SLE classification criteria.  The revision that was made stated that a person could be classified for having SLE if there was proven kidney-related involvement (lupus nephritis) after a complete biopsy.  This would also involve the presence of anti-dsDNA or ANA antibodies along with at least 4/11 diagnostic criteria, one or more symptoms, and a positive test. 

There are several lab tests available for spotting these autoantibodies in the system for a lupus diagnosis. 

These can include: 

Additional tests that can be used to diagnose a patient with lupus include: 

  • Complete Blood Count (CBC) – Helpful for spotting signs of low white blood cell count, low platelet count, and anemia as may occur in patients with lupus 
  • Urinalysis – Can show urinary casts, blood, or protein in the urine  
  • Serum protein electrophoresis (SPEP) – Helpful for spotting gamma globulin protein levels often cited alongside conditions such as SLE 
  • Comprehensive metabolic panel (CMP) – Ideal for assessing the patient’s liver and kidney production along with blood glucose levels, blood proteins, and acid/base balance. 
  • Erythrocyte sedimentation rate (ESR or SED rate) – Can help showcase signs of inflammation, which is commonly seen in patients with lupus and/or other relevant inflammatory conditions 
  • Complement 3 (C-3), CH50, and C4 – Can assist with understanding decreased production in the immune system but can also be an indicator of malaria, shock, or gram-negative septicemia  
  • C-reactive protein (CRP) – Can help spot inflammation  
  • Cryoglobulin – Can come back positive for high levels of this abnormal protein in the blood that will precipitate with reduced body temperature, leading to blockage of the blood vessels 

Non-laboratory tests include X-rays and other imaging used to look at particular organs potentially affected by lupus.  Also, a kidney biopsy may be run to find any changes that could point to lupus and/or guide treatment.