When Your Doctor Said “SED,” What Did They Mean?
It’s a phrase common to hear during blood work, but many people don’t understand what it means for them.
“Everything’s fine,” your doctor tells you upon receiving your blood-work results. “But your sed rate’s a little high.” Embarrassed to ask, “What’s a sed rate?” you smile, thank her, and leave. But an elevated sed rate or ESR (erythrocyte sedimentation rate) can indicate that you may have an inflammatory disease, and noting changes in it can help your doctor monitor the progress of a disease if there is one.
The ESR “is a measure of red blood cells (erythrocytes) settling or sedimenting in a tube over one hour,” says Jack Berger, MD, a rheumatologist at WESTMED Medical Group. “The sed rate depends on several blood factors including red blood-cell count, hemoglobin, total protein, gamma globulins, and the viscosity (thickness) of the serum.” The normal range for a sed rate is 0-20 mm/hour. An elevated rate “could be a sign of inflammation,” says Dr. Berger. “This may be a rheumatic disease such as polymyalgia rheumatica, temporal arteritis, rheumatoid or other types of arthritis. Also, infections and some blood disorders can cause an elevated ESR, and further tests can usually clarify the cause.”
If your doctor says your sed rate is elevated, don’t freak out. “Occasionally, a person may have a mildly elevated ESR without any explanation,” says Dr. Berger, who also cautions that what’s “normal” for one person may not be for another, and you should consult your doctor to see if further evaluation is necessary.