Description
The sedimentation rate blood test measures how quickly red blood cells (erythrocytes) settle in a test tube in one hour. The more red cells that fall to the bottom of the test tube in one hour, the higher the sedimentation rate.
When inflammation is present in the body, certain proteins cause red blood cells to stick together and fall more quickly to the bottom of the tube.
These proteins are produced by the liver and the immune system under many abnormal conditions, such as an infection, autoimmune disease, or cancer.
There are many possible causes of a high sedimentation rate. For this reason, a sed rate is done with other tests to confirm. After a diagnosis has been made, a sed rate can be done to check on the disease or see how well treatment is working.
Sedimentatuion rate is measured by means of analysis of a blood sample drawn from the vein in the arm.
Purpose of the test
The sedimentation rate blood test measures how quickly red blood cells settle in a test tube.
A sedimentation rate test is done to:
- Find out if inflammation is present.
- Check on the progress of a disease.
- See how well a treatment is working.
Reference range values
Men : <15 mm/hr
Women : <20 mm/hr
Children : <10 mm/hr
Newborns : <2 mm/hr
Abnormal findings
High sedimentation rates may be caused by:
- Autoimmune diseases, such as systemic lupus erythematosus or rheumatoid arthritis.
- Cancer, such as lymphoma or multiple myeloma.
- Chronic kidney disease.
- Infection, such as pneumonia, pelvic inflammatory disease, or appendicitis.
- Inflammation of joints (such as polymyalgia rheumatica) and blood vessels (such as giant cell arteritis).
- Inflammation of the thyroid gland (Graves' disease).
- Kidney, bone, joint, skin, or heart valve infections.
- Pregnancy and preeclampsia (toxemia of pregnancy).
- Viral infections.
Low values of sedimentation rate may be caused by:
- High blood sugar levels.
- Polycythemia.
- Sickle cell disease.
- Severe liver disease.