A Quick Glance at the Tests Used for Rheumatoid Arthritis Diagnosis
Posted Oct 16 2008 8:11am
When I was diagnosed with Rheumatoid Arthritis in 2005, I had one blood test performed and some x-rays ordered, and at the time that was my extent of knowledge to the range of possibilities in diagnosing the disease. Learning more about RA caused me to look into the tests that are beneficial in proper diagnosis, and in turn, understanding what the tests actually did helped me understand more about the disease.
I had an Rh factor test (a simple blood test) taken which turned out to be positive. Antibodies are normal proteins found in the blood; the Rh (Rheumatoid) factor is an antibody that can bind or attach itself to other antibodies. The Rh factor isn’t usually found in normal population; however it is found in over 80% of adults who have RA.
A general CBC(Complete Blood Count) test may be ordered to measure red blood cells, their number, fraction and size; it also measures the number of white blood cells, and the amount of hemoglobin in the blood. This will the Dr an idea of there’s infection, or any other condition going on.
I’m glad I just have to type this next one out, if I tried to pronounce it I’d mess up! Erythrocyte Sedimentation Rate (ESR) should be called the ‘inflammation measuring test’ because that’s what it does; it measures how much inflammation is in the body.
The C - Reactive Protein test is a little trickier which measures a special type of protein produced by the liver. During a time of acute inflammation or infection the liver will secrete this protein and the CRP measures the concentration of this protein in blood serum. Although it’s not specific, a high result of the protein gives a general indication of intense inflammation and Rheumatoid Arthritis causes a large amount of inflammation, especially during flare-ups. Because it’s not specific, a high CRP rate could also be indicative of rheumatic fever, lupus, cancer, tuberculosis, heart attack or pneumonia.
This next test sounds to me more like a weapon or air craft – the HLA B27. It’s a gene marker affiliated with quite a few related rheumatic conditions. They have a few things in common such as peripheral arthritis (affects the large joints of the body) and spinal arthritis, skin and gastro-intestinal disorder, certain glaucoma, and psoriasis like skin lesions. This isn’t a usual test that A Doctor would perform because a lot of patients with this gene never develop any rheumatic symptoms.
Antinuclear Antibody (ANA) is a blood sample specimen from the patient, put onto microscope slides that have been commercially prepared with cells, to look for antinuclear antibodies. If the patient’s serum does contain the ANA, they will bind to the cells on the slide (particularly the nuclei of the cells).
A second commercially fluorescent tagged antibody is then added to the serum and prepared cells on the slide. The fluorescent antibody attaches to the serum antibodies and cells which have bound together, and when it’s viewed under an ultraviolet microscope, the ANA appear as fluorescent cells.
ANA’s are discovered in people who various autoimmune diseases, but can be also found in patients with infections, lung disease, cancer, GI diseases, hormonal disease, blood diseases, and skin diseases. Having ANA tests performed is only one factor in diagnosing RA, other factors need to be considered such as symptoms, medical history and other medical tests.
Anti-Cyclic Citrullinated Peptide Antibody (Anti-CCP) test is a fairly new test being preformed to help doctors diagnose Rheumatoid Arthritis. It measures the citrulline antibody, and if it is a moderate to high level it not only confirms the diagnosis but also may show that the patient is at an increased risk for damage to joints.
One last test that I found was on Synovial Fluid, the thick fluid found in cartilage which reduces friction between joints and adds lubrication and cushioning during movement. Analyzing the synovial fluid helps detect markers of joint destruction, but this is not a test that is usually performed because it’s not the most comfortable test. A sterile needle is inserted into the joint space, and fluid is then aspirated into a syringe. The specimen is then analyzed in a laboratory and examined for red and white blood cells, crystals (in case of gout), and bacteria.
X-rays, ultra-sound and MRI’s are commonly performed in order to determine the possibility and extent of joint damage, in order to give doctors a better understanding of the intensity of the condition.
Initially these are the some of the first tests that are preformed especially during the diagnosis process.
While waiting for the results of my Rh factor test, I went through a roller coaster of thoughts and images in my mind. Sometimes I was optimistic, sometimes pessimistic and sometimes in complete denial. How did you feel while waiting for your results?