ESRDefinition: 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.
Alternative Names: Erythrocyte sedimentation rate; Sed rate; Sedimentation rate
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.
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. Although it is a screening test (cannot be used to diagnose a specific 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.
Normal Values: 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: Markedly elevated values occur with: Lower-than-normal levels occur with: Additional conditions that may affect test results: - Allergic vasculitis
- Atrial myxoma, left
- Atrial myxoma, right
- Autoimmune hepatitis
- Endometritis
- Eosinophilic fasciitis
- Erysipelas
- Juvenile rheumatoid arthritis
- Legionnaire's disease
- Osteomyelitis
- 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
Special considerations: 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.
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