Rheumatoid Arthritis Diagnosis
What determines a rheumatoid arthritis diagnosis? Is there a blood test that indicates
an accurate diagnosis? While there is no one blood test that accurately diagnoses
rheumatoid arthritis, there are a set of guidelines which include blood tests and
examinations to distinguish rheumatoid arthritis from other forms of arthritis and
other rheumatic diseases.
A rheumatoid arthritis diagnosis is a clinical diagnosis and must include, in addition
to blood tests, an examination of other factors-especially affected joints. Factors
such as morning stiffness greater than one hour, symmetric joints affected, usually
three or more joints affected especially in the hands, wrist, ankles, knees, or
elbows, or only two symmetrical joints affected plus a positive RF test, are required
to determine a rheumatoid arthritis diagnosis. Blood tests alone are inconclusive
for an accurate diagnosis and all factors must be evaluated together.
Several blood tests are used for rheumatoid arthritis diagnosis. The rheumatoid
factor (RF) test is used to detect the presence of the rheumatoid factor anti-body.
This test is not always accurate, but when present, especially with a high factor,
indicates the severity of the disease in a patient.
The erythrocyte sedimentation rate (ESR) or "sedrate" test measures the presence
of inflammation and is used to monitor treatment as well as an initial indicator
that the arthritis symptoms may be from rheumatoid arthritis instead of osteoarthritis.
The anti-CCP (anti-cyclic citrullinated peptide antibody) test is a new and useful
test especially in early diagnosis of rheumatoid arthritis.
The antinuclear antibody (ANA), anti-DNA, and anti-Sm tests are useful in distinguishing
between rheumatoid arthritis and Lupus.
C-Reactive Protein (CRP) test is ordered to detect when acute inflammation is present.
A complete blood count (CBC) test is also usually ordered both for diagnosis of
rheumatoid arthritis as well as for monitoring the progression of the disease and
treatment. This test is useful for monitoring anemia, detecting the presence of
infection or inflammation, and for distinguishing between the causes of inflammation.
While this list is not a complete list of all blood tests used in a rheumatoid arthritis
diagnosis, it covers the major tests used today. Since a rheumatoid arthritis diagnosis
is a clinical diagnosis all these factors must be included for an accurate diagnosis.
None of the blood tests alone are conclusive for an accurate diagnosis and all factors
must be evaluated together for each individual case.