Tests For Arthritis: A Rundown On Some Of The Tests That Help Diagnose This Common Inflammatory Disease
How Are Tests For Arthritis Helpful?
There are many forms of arthritis. It is not sufficient to know that a person generally has arthritis, but it is instead important to know which kind of arthritis from which a person suffers. This is true because some forms of arthritis need to be treated much differently than other forms.
Fortunately, these are many options that are available to the clinician in making this determination. These options include body sample-based tests that measure levels of certain compounds in a particular body sample (usually the blood) and mechanical devices that can be used to test a patient for hallmark signs of various forms of arthritis.
Body Sample-Based Tests
There are several body sample-based tests that are available for diagnosing arthritis, some of which are used to measure the amount of, or to merely detect the presence of, a particular compound in the blood. Often used tests of this kind include:
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Rheumatoid factor test. An antibody that is designated “rheumatoid factor” is produced by the body’s immune system in individuals who suffer from rheumatoid arthritis. This test simply detects the presence or absence of this antibody.
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Antinuclear antibody test. Like the rheumatoid factor test, the antinuclear antibody test determines whether certain antibodies that are characteristic of arthritis are present in a person’s blood.
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C-reactive protein test. C-reactive protein is normally synthesized in small amounts by the liver, but becomes produced in larger amounts whenever the body experiences inflammation. The presence of elevated C-reactive protein in the blood is therefore suggestive that the person being tested suffers from arthritis, as inflammation is a hallmark symptom of arthritis. However, it should be noted that a positive C-reactive protein test also may be indicative of a non-arthritic condition that causes inflammation. For this reason, clinicians usually perform other tests in conjunction with the C-reactive test when determining whether a person has arthritis.
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Erythrocyte sedimentation test. This test, which is also called the sed rate test, measures the rate at which erythrocytes (red blood cells)obtained from the person being tested for arthritis settle to the bottom of a buffer solution. If the person is experiencing inflammation, the cells will clump and settle more slowly than they would if no inflammation was present.
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Hematocrit test. This tests measure the number of red blood cells that are present in a particular volume of blood. People who have arthritis generally have fewer red blood cells than do healthy individuals.
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White blood cell test. This test is similar to the hematocrit test. A low white blood cell count is suggestive that a person has rheumatoid arthritis (whereas a high white blood cell count is suggestive of infection).
Mechanical Device-Based Tests
In addition to the body sample-based tests listed above, clinicians also perform device-based tests to determine whether a person is suffering from arthritis. The types of devices that are sometimes used in making this determination include:
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X-ray machines. Clinicians use x-ray machines to determine whether swelling is present, and if so, the extent of the swelling.
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CAT scan machine. Like x-ray analysis, CAT scans help show whether inflammation is present. CAT scans are preferred to x-rays as they show greater detail. (However, CAT scans are also much more expensive than are x-rays.)
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MRI machines. MRI images also depict body joints in a detailed manner, which enables clinicians to detect swelling.
References
Arthritis Today, The Arthritis Foundation, Lab Test Guide: https://www.arthritistoday.org/treatments/lab-test-guide.php
Mayo Clinic, Rheumatoid arthritis: Tests and diagnosis. https://www.mayoclinic.com/health/rheumatoid-arthritis/DS00020/DSECTION=tests-and-diagnosis
The University of Chicago Medical Center, _Diagnosing Arthritis and Other Rheumatic Disease_s: https://www.uchospitals.edu/online-library/content=P00050