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A New Free Report - What Is Lupus?
This fascinating new report from UK-based publishing house Health Research Today answers some of the most-asked questions about this baffling disease :
- What is the medical definition of lupus?
- What are the symptoms of lupus?
- What tests are there for lupus? How do you get a diagnosis?
Fill in this form and we will send you the report immediately, which you are welcome to send on to friends or family!
Tests for Lupus
This article is an extract from the ebook Freedom From Lupus!
Many of the symptoms associated with lupus are also associated with other disorders. Therefore one of the ACR criteria involves having a positive ANA test for lupus. However, doctors use a variety of other testing to also confirm a lupus diagnosis:
Anti-Sm Antibody
The antibody to the smith antigen test, or anti-Sm test, works with the anti-RNP, anti-Ro/SSA, and anti-La/SSB to make up the ENA antigens. The Smith antigen is a protein that helps keep DNA in its correct shape while it works to communicate with other cells ways to effectively work.
A positive test usually means that lupus is present, and false positive tests are extremely rare. Despite the fact that a positive anti-Sm antibody test will confirm lupus, a negative test does not eliminate the option. Other lupus related tests might show positive results even if the anti-Sm antibody test is negative. However, most lupus patients have either a positive anti-DNA or positive anti-Sm antibody test. In most cases a negative test for both means that the patient does not have lupus. However, only 10 percent of lupus patients have a positive anti-Sm test, but 90 percent of people who have positive Sm tests have lupus.
Blood Component Level Test
Blood component Level tests are designed to measure a specific concentration of a component of the complement system in the blood. Patients with active SLE usually have below normal C3 and C4 levels in the blood. Normally females have C3 or C4 levels of 13 to 75 mg/dL, and males have levels of 12 to 72 mg/dL.
Complement is a group of proteins that help the immune system response and inflammation. There is a complement cascade that involves the different reactions in the blood. There are 9 major components of complement labeled C1 through C9. The final part of the cascade is when the terminal complement component, or “membrane attack unit,” creates a hole in the membrane to kill the bacteria.
The common tests for the activity of the complement system of CH50 and CH100. These tests determine if complement is involved in the development of lupus and to determine how serious the lupus is. However, the blood component level test is usually not the first test performed to determine if lupus is present, as there are much more specific tests available.
Scans
MRI and CT scans are often used on lupus patients to diagnose CNS lupus. MRI stands for “magnetic resonance imaging.” It is a radiology technique that combines magnetism and radio waves to produce images of the body and organs on a computer monitor. The MRI machine is a large tube surrounded by an even larger circular magnet, and while the test is painless, there is a lot of noise involved.
A CT scan, also known as a CAT scan, is an x-ray procedure. The CAT stands for “computed axial tomography.” The scan takes multiple x-ray images and puts them together to create cross-sectional pictures of soft tissue, bone, and blood vessels. The CT scan is effective for examinations of areas that cannot be seen with a standard x-ray.
Abnormalities seen on an MRI are not specific for SLE, so the scan is often used in conjunction with other tests. MRIs and CT scans can be used to check for blood clots, inflammation, brain hemorrhages, or fluid in the joints.
Tissue Biopsy
A biopsy is the removal of tissue for examination under a microscope. A tissue biopsy can be taken from various areas and for a variety of reasons. When the primary symptom for a potential lupus patient is a rash on the skin, as it is with DLE, a biopsy of the skin is done and examined. Skin lesions for lupus look different under a microscope, and it facilitates the diagnosis. However, a “positive band test” is only important if the tissue comes from an area other than the rash.
Kidney disease can also be diagnosed via a biopsy. The examination of a tissue sample from the kidney can demonstrate SLE even in severe kidney disease. Tissue biopsies are effective at showing deposits of antibodies and immune system complexes that point toward lupus being present in the kidney filtration area.
Any results found from a tissue biopsy should be interpreted along with a clinical history. A tissue biopsy alone will not necessarily confirm a lupus diagnosis.
Schirmer’s Test
The Schirmer’s test is one of the most underused tests in rheumatology. The test is very inexpensive (under one dollar per tests) and takes up little of the patient’s time. The dry Schirmer’s test involves inserting blotting paper into the lower eyelid and having the patient close his or her eyes for five minutes. While it is irritating, it is often wet in seconds and its results help in the diagnosis of autoimmune diseases.
A negative result occurs if there is more than 10 mm of moisture on the filter paper after five minutes. This test is often used in the diagnosis of dry eyes associated with Sjogren’s syndrome. Sjogren’s syndrome can coexist with SLE, and it is not uncommon to find features associated with Sjogren’s syndrome in SLE patients.
Since the Schirmer’s test can be used in the process of diagnosing lupus, it cannot be used alone. It can be combined with other tests to make a case for the diagnosis of lupus. It also points toward the shared diagnosis with Sjogren’s syndrome, which will help direct doctors toward proper treatment.
Read the rest of this article in Freedom From Lupus!
© Health Research Today
