Erythrocyte sedimentation rate; Sed rate; Sedimentation rate
ESR (erythrocyte sedimentation rate) is a nonspecific screening test for various diseases. This 1-hour test measures the distance (in millimeters) that red blood cells settle in unclotted blood toward the bottom of a specially marked test tube.
How the test is performed
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a band or blood pressure cuff is placed around the upper arm to apply pressure and cause the veins below the band to fill with blood.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children:
The area is cleaned with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any continued bleeding.
How to prepare for the test
There are no food or fluid restrictions.
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child’s age, interests, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child’s age:
- Infant test or procedure preparation (birth to 1 year)
- Toddler test or procedure preparation (1 to 3 years)
- Preschooler test or procedure preparation (3 to 6 years)
- Schoolage test or procedure preparation (6 to 12 years)
- Adolescent test or procedure preparation (12 to 18 years)
How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the test is performed
The erythrocyte sedimentation rate (ESR) can be used to monitor inflammatory or malignant disease, rheumatic fever, and heart attack. Although it is a screening test (not considered diagnostic for any particular disorder), it is useful in detecting and monitoring tuberculosis, tissue necrosis (death), rheumatologic disorders, or an otherwise unsuspected disease in which symptoms are vague or physical findings are minimal.
Adults (Westergren method):
- Men under 50 years old: less than 15 mm/hr.
- Men over 50 years old: less than 20 mm/hr.
- Women under 50 years old: less than 20 mm/hr.
- Women over 50 years old: less than 30 mm/hr.
Children (Westergren method):
- Newborn: 0 to 2 mm/hr.
- Neonatal to puberty: 3 to 13 mm/hr.
Note: mm/hr. = millimeters per hour.
What abnormal results mean
Elevated values occur with:
- Kidney disease
- Rheumatic fever
- Rheumatoid arthritis
- Severe anemia
- Systemic lupus erythematosus
- Thyroid disease
Markedly elevated values occur with:
- Giant cell arteritis
- Multiple myeloma
- Macroglobulinemia - primary
- Hyperfibrinogenemia (elevated fibrinogen levels in the blood)
- Necrotizing vasculitis
- Polymyalgia rheumatica
Lower-than-normal levels occur with:
- Congestive heart failure
- Hypofibrinogenemia (decreased fibrinogen levels)
- Low plasma protein (due to liver or kidney disease)
- Sickle cell anemia
Additional conditions that may affect test results:
- Allergic vasculitis
- Atrial myxoma, left
- Atrial myxoma, right
- Autoimmune hepatitis
- Eosinophilic fasciitis
- Juvenile rheumatoid arthritis
- Legionnaire’s disease
- Pelvic inflammatory disease (PID)
- Pericarditis, post-MI
- Retroperitoneal fibrosis
- Skin lesion of blastomycosis
- Subacute thyroiditis
- Systemic sclerosis (scleroderma)
What the risks are
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
- Multiple punctures to locate veins
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
by Janet G. Derge, M.D.
All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.