Understanding Lupus Labs
Complete Blood Count
This is a comprehensive, routine test which measures the number of red blood cells, white blood cells and platelets as well as the amount of hemoglobin, a protein in red blood cells. Results may indicate you have anemia, which commonly occurs in lupus. A low white blood cell or platelet count may occur in lupus as well.
The results of this test allows your doctor to see the overall immune activity, which then will provide your doctor direction on what other tests are necessary to further investigate your disease or health.
Erythrocyte Sedimentation Rate (ESR)
Provides an indirect, but functional marker for increase in plasma fibrinogen and immunoglobulins.
This test measures the rate at which red blood cells settle to the bottom of a test tube in an hour. A faster than normal rate may indicate a systemic disease, such as lupus.
The sedimentation rate isn't specific for any one disease. It may be elevated if you have lupus, another inflammatory condition, pregnancy, hypothyroidism, cancer or an infection.
This value can be high in various conditions:
- Rheumatoid Arthritis
- Inflammatory Bowel Disease
- Multiple Myeloma
- Hodgkins' Lymphoma
- Chronic Kidney Disease
A complete urinalysis evaluates several different aspects of your urine through physical, chemical, and microscopic examination. A urinalysis is often used in Lupus patients to monitor protein leakage (indicating kidney involvement) and identify and assess urinary tract infections (UTIs).
Kidney and Liver Assessment
Liver and Kidney enzymes will be assessed if your doctor suspects Kidney or Liver involvement with your Lupus.
If the protein is high in your urine, it can be indicative of a nephrotic syndrome which is the result of antibodies attacking your kidneys. A kidney biopsy is sometimes warranted to assess the extent of kidney involvement and to determine which treatment approach to prescribe for your condition.
Elevated liver enzymes may indicate an inflammatory condition and your doctors will assess this value to collectively evaluate your Lupus involvement. Isolated elevation of liver enzymes in and of themselves do not indicate a definitive condition, rather it's the collective whole that your doctor must assess to differentiate your disease progression.
This protein is produced by the liver in response to inflammatory condition. It typically increases after tissue injury or infection.
Increase in C-reactive Protein can be indicative of Lupus, Pelvic Inflammatory Disease, and Infection after surgery.
CRP is not an accurate measurement of disease activity because the levels can be normal with active inflammatory disease, cancer, and Lupus.
ANA (Anti-Nuclear Antibody)
ANA is the one of the hallmark tests that's performed when suspecting an "autoimmune condition". With that being said, approximately 15% of healthy individuals test positive with ANA.
ANA is a group of autoantibodies produced by a person's immune system when it fails to differentiate from self to non self and begin attacking its own cells.
ANA results do not differentiate one autoimmune condition from another. If tested positive, its indicative of an autoimmune condition, however, further testing is required to make a final diagnosis.
- ANA are most commonly seen with SLE. Approximately 95% of those with SLE have a positive ANA. If someone also has symptoms of SLE, such as arthritis, a rash, and sun sensitivity, then the person likely has SLE. A positive anti-dsDNA and anti-SM (often ordered as part of an Lupus panel) help confirm that the condition is SLE.
Your doctor must rely on test results, clinical symptoms, and your history for diagnosis. Because symptoms may come and go, it may take months or years to show a pattern that might suggest SLE or any of the other autoimmune diseases.
A negative ANA result makes SLE an unlikely diagnosis. It usually is not necessary to immediately repeat a negative ANA test; however, due to the tempermental nature of autoimmune diseases, it may be worthwhile to repeat the ANA test at a future date if symptoms recur.
Typically, further autoantibody (subset) testing is not necessary if a person has a negative ANA result.
About 3-5% of healthy Caucasians may be positive for ANA, and it may reach as high as 10-37% in healthy individuals over the age of 65 because ANA increases with age. Such instances are more common in women than men.
Complements are the integral component of innate immunity: they are a complex of small, circulating proteins that bind to pathogenic structure, initiating cascade of proteases and production of immune activating protein fragments.
Total Hemolytic Activity (CH50), C3, and C4 are typically "low" in Lupus and autoimmune diseases when disease activity is high.
Here's the run down on some tests that your "conventional" rheumatologist may not typically assess.
Complement split products: C3a, C4a, C5a
C3a is increased with:
- Acute Lyme (along with increased C4a)
- Active Lupus (+/- increased C4a)
-Type 1 interferons: IFN-alpha, IFN-beta, IFN-y
Tumor Necrosis Factors
Transforming Growth Factors
Anti-Double Stranded DNA
The anti-double-stranded DNA antibody (anti-dsDNA) is a specific type of ANA antibody found in about 30% of people with systemic lupus. Less than 1% of healthy individuals have this antibody, making it helpful in confirming a diagnosis of systemic lupus. [The absence of anti-dsDNA, however, does not exclude a diagnosis of lupus.]
The anti-dsDNA test may be used to verify that you indeed have Lupus and to monitor disease activity if you do have Lupus. An increased anti-dsDNA level may be seen prior to and during these flare-ups. In particular, this test may be used to monitor lupus nephritis, a serious complication of lupus that can cause kidney damage and inflammation.
Higher levels may indicate an impending flare or assess the severity of Lupus and its potential involvement with Kidney Nephritis as a secondary result of Lupus.
Anti Smith Antibody
An antibody to Sm, a ribonucleoprotein found in the nucleus of a cell, is found almost exclusively in people with lupus. It is present in 20% of people with Lupus, but it is rarely found in people with other rheumatic diseases and its incidence in healthy individuals is less than 1%.
Therefore, it can also be helpful in confirming a diagnosis of systemic lupus. Unlike anti-dsDNA, anti-Sm does not indicate kidney involvement.
If you were positive at the onset, it is one that will be measured for disease progression and/or activity.
Anti-U1RNP antibodies are commonly found along with anti-Sm antibodies in people with Lupus. Approximately 25% of Lupus patients have it and less than 1% of healthy individuals possess this antibody. However, anti-U1RNP antibodies are not specific to lupus; they can be found in other rheumatic conditions, such as rheumatoid arthritis, systemic sclerosis, Sjogren’s syndrome, and polymyositis. This biomarker is not a significant indicator for disease activity.
Anti Phospholipid Antibodies
Antiphospholipid antibodies are antibodies directed against phosphorus-fat components of your cell membranes called phospholipids. Approximately 50% of people with lupus are positive for these antibodies. People without lupus can also have antiphospholipid antibodies.
The presence of an antiphospholipid antibody such as the lupus anticoagulant and anticardiolipin antibody in an individual is at risk for blood clots. This antibody is is important because it can cause fetal loss and/or miscarriages, blood clots of the veins or arteries (thromboses), low platelet counts (autoimmune thrombocytopenia), strokes, transient ischemic attacks (stroke warnings), Libman-Sacks endocarditis (formation of a clot on a specific heart valve), pulmonary emboli, and pulmonary hypertension.
Anti Ro/SSA and Anti La/SSB Antibodies
Anti-Ro/SSA and Anti-La/SSB are found in approximately 30-40% of those with Lupus and primary Sjogren’s syndrome. They are also commonly found in people with lupus who have tested negative for anti-nuclear antibodies.
Anti-Ro and anti-La can also be found in other autoimmune conditions, such as systemic sclerosis, rheumatoid arthritis, and polymyositis, and can be positive in approximately 15% of healthy individuals. These antibodies can indicate a sun sensitivity, a clinical subset of lupus called subacute cutaneous lupus erythematosus (SCLE).
Important to not that lupus-like syndrome associated with a genetic deficiency of a substance called complement (a system of proteins that helps mediate your body’s immune response). In addition, babies of mothers with anti-Ro and anti-La antibodies are at an increased risk of neonatal lupus, an uncommon condition that produces a temporary rash and can lead to congenital heart block. Therefore, women with lupus who wish to become pregnant should be tested for these antibodies.
Your doctor may test for Antibodies to histones, which are proteins that help to lend structure to DNA. These antibodies are usually found in people with drug-induced lupus (DIL), but they can also be found in people with lupus. But important to note that this test is not specific to Lupus.
Comprehensive Lipid Profile may be assessed because the common medication that is prescribed, prednisone, my cause elevated lipid levels.
Typically, this is a temporary level which normalizes after ceasing to use prednisone.
Prednisone usage raises the likelihood of induced diabetes so your doctor will check to ensure safe levels.
24 hour Urine
If your doctor suspects kidney involvement, you will be referred to a nephrologist and he/she will request a collection of urine for 24 hours to evaluate protein in your urine.
If levels are significantly high they will likely want perform a kidney biopsy to determine the level of involvement to prescribe the best treatment approach.
Use of Prednisone will increase your likelihood for osteopenia and/or osteoporosis so your doctor will test this to see what your risks are to treat appropriately. Your insurance should pay for this if you are at risk every 2 years.
Side note: It is far wiser to take Vitamin K, Calcium, and Magnesium in proper balance in conjunction to load bearing exercises to ensure you are building bone.
- Wallace, Daniel J., and Bevra Hannahs Hahn, eds. Dubois’ Lupus Erythematosus. 7th ed. Philadelphia: Lippincott Williams & Wilkins, 2007.
- “Blood Tests.” The Lupus Site. 6 July 2009.
- “Laboratory Tests.” Lupus Foundation of America. 6 July 2009.
- “ANA.” 8 April 2009. Lab Tests Online. 8 April 2009. American Association for Clinical Chemistry. 6 July 2009.
- Wallace, Daniel J. The Lupus Book: A Guide for Patients and Their Families. 1st ed. New York: Oxford University Press, 1995.