Subject | Contents |
Definition | A nonspecific screening test for various diseases. The test measures the distance (in millimeters) that red blood cells settle in unclotted blood toward the bottom of a specially marked test tube in 1 hour. |
Alternative Names | Erythrocyte sedimentation rate; Sed rate; Sedimentation rate |
How the test is performed | Adult or child: Blood is drawn from a vein ( venipuncture ), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (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 tourniquet 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 . Infant or young child: The area is cleansed 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. Cotton or 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 acute myocardial infarction . Although it is a screening test (not considered diagnostic for any particular disorder), it is useful in detecting and monitoring tuberculosis , tissue necrosis (tissue death), rheumatologic disorders, or an otherwise unsuspected disease in which symptoms are vague or physical findings are minimal. |
Normal Values | (Westergren method) Adults: 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. Pediatric: 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 diseasepregnancyrheumatic feverrheumatoid arthritis severe anemiasyphilissystemic lupus erythematosusthyroid diseasetuberculosis Markedly elevated values occur with: giant cell (temporal, cranial) arteritismultiple myelomamacroglobulinemia - primary hyperfibrinogenemia (elevated fibrinogen levels in the blood)necrotizing vasculitispolymyalgia rheumatica Lower-than-normal levels occur with: congestive heart failurehyperviscosityhypofibrinogenemia (decreased fibrinogen levels) low plasma protein (e.g., due to hepatic (liver) or renal disease )polycythemiasickle cell anemia Additional conditions that may affect test results: allergic vasculitisatrial myxoma; leftatrial myxoma; rightautoimmune hepatitisendometritiseosinophilic fasciitiserysipelasjuvenile rheumatoid arthritisLegionnaire's diseaseosteomyelitispelvic inflammatory disease (PID)pericarditis; post-MIretroperitoneal fibrosisskin lesion of blastomycosissubacute thyroiditissystemic sclerosis (scleroderma) |
What the risks are | excessive bleedingfainting 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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