The sedimentation, or sed, rate test is most often used to help diagnose giant cell arteritis, polymyalgia rheumatica and rheumatoid arthritis, according to Mayo Clinic. Sed rate tests alone do not confirm diagnoses, so they are typically used in conjunction with other blood assessments, such as the C-reactive protein test.
In giant cell arteritis, the lining of the arteries, which carry blood away from the heart, becomes inflamed, reports Mayo Clinic. This most often occurs in temple arteries. The condition typically produces headaches, jaw pain and blurred or double vision, but blindness and stroke occasionally occur. If not treated soon enough, permanent tissue damage and vision loss occur.
In seniors, polymyalgia rheumatica displays general symptoms of stiff and aching joints, most often in the shoulders and upper arms, states American College of Rheumatology. In the morning, symptoms are at their worst. Swelling is usually not present, which makes diagnosis more difficult. PMR sometimes accompanies giant cell arteritis.
When the body's immune system incorrectly launches an assault on its own joints, rheumatoid arthritis occurs, Arthritis Foundation says. The resulting inflammation leads to joint and organ damage. In some cases, the heart is affected. The disease is most common in women, when it typically appears between the ages of 30 and 60. Men tend to develop the disease later in life.