ERYTHROCYTE SEDIMENTATION RATE BENYAH SAMUEL OBJECTIVES Definition Principle

ERYTHROCYTE SEDIMENTATION RATE BENYAH SAMUEL

OBJECTIVES �Definition �Principle of test �Procedure �Interpretation �Clinical Significance �False Negative

DEFINITON �The erythrocyte sedimentation rate (ESR or sed rate) is the rate at which red blood cells sediment in a period of one hour. It is a common hematology test, and is a non-specific measure of inflammation. �ERYTHROCYTE - RBC �SEDIMENTATION - LAYERS �RATE - TIMING

Westergren tube

Principle of the test �The Erythrocyte Sedimentation Rate (ESR) is a nonspecific assay used to screen for the presence or absence of active disease. The settling of red corpuscles (red blood cells - RBCs) is due to the differential densities of the RBCs and their medium. Most often, an increased ESR is due to an increased amount of plasma proteins (i. e. , acute phase globulins) and less commonly to inherent characteristics of RBCs (Wintrobe 30). ESR is measured in mm/hr using the Modified Westergren Method.

�Erythrocyte aggregation is a physiological phenomenon that takes places in normal blood under low-flow conditions or at stasis. The presence or increased concentrations of acute phase proteins, particularly fibrinogen, results in enhanced erythrocyte aggregation.

MECHANISM OF SEDIMENTATION

SPECIMEN REQUIREMENTS �. Ø Whole Blood Collected. 1. 6 Ml Ø Edta Ø Westergren Tube Ø Watch Clock Ø Rack �Specimens must be brought to the laboratory within 4 hours of the blood draw if kept at room temperature. Alternately, whole blood may be refrigerated and brought to the laboratory within 12 hours of the blood draw. Clotted or hemolyzed samples are not acceptable.

�Conditions which cause increased rouleaux formation include �Infections �Inflammatory �Connective tissue disorders �Cancers.

Clinical Diagnosis � Multiple myeloma, � Temporal arteritis, � Polymyalgia rheumatica � Various auto-immune diseases, � Systemic lupus erythematosus, �Rheumatoid arthritis, � Inflammatory bowel disease �Chronic kidney diseases.

Normal range Male Female 50 yrs. old or less 15 mm/hr 20 mm/hr >50 yrs old (50+) 20 mm/hr 30 mm/hr

FALSE NEGATIVE �Renal disease �Female sex (pregnancy) �Older age increase the erythrocyte sedimentation rate. �Obesity �Anemia

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