Which of the following is a good use of the erythrocyte sedimentation rate (ESR)?

a. Monitor patients with rheumatoid arthritis.
b. Diagnose acute appendicitis.
c. Diagnose multiple myeloma.
d. Monitor patients with osteoarthritis.

ANS: A
The ESR is elevated in patients with rheumatoid arthritis. It decreases when the disease is in remission and increases when it exacerbates; therefore it is useful for monitoring this disease. It is normal in the first 24 hours of acute appendicitis, so is not useful in diagnosis. It is elevated in multiple myeloma, but also in many other clinical conditions, so it is not diagnostic for it. It is normal in osteoarthritis and thus of no value for monitoring those patients.