Erythrocyte Sedimentation Rate

ERYTHROCYTE SEDIMENTATION RATE

DEFINITION THE RATE AT WHICH RED CELLS FALL WHEN ANTICOAGULATED BLOOD IS ALLOWED TO SETTLE UNDER THE INFLUENCE OF GRAVITY IS CALLED ERTHROCYTE SEDIMENTATION RATE. OCCURS DUE TO ROULEAU FORMATION OF RBC’S.

FACTORS AFFECTING ESR SIZE OF THE ROULEAUX PLASMA FACTORS:-

FIBRINOGEN ACUTE PHASE REACTANTS GLOBULIN VISCOSITY

SHAPE OF THE RBC’S TECHNICAL AND MECHANICAL FACTORS TEMPERATURE POSITION

METHODS OF DETERMINATION

WESTERGEN METHOD APPARATUS REQUIRED:WESTERGEN’S TUBE WESTERGEN’S RACK

REAGENT USED:3.8% SODIUM CITRATE

PROCEDURE:BLOOD OBTAINED BY VENUPUNCTURE IS MIXED WITH THE REAGENT IN THE RATIO 4 :1. FILL THE TUBE UPTO THE ‘0’ MARK.. KEEP IT IN THE RACK PROPERLY. READ AFTER ONE HOUR.

PRECAUTIONS CONCENTRATION OF THE REAGENT SHOULD BE CORRECT. BLOOD SHOULD BE PROPERLY MIXED WITH THE REAGENT. PIPETTE SHOULD BE CLEAN AND DRY. BLOOD SHOULD BE FILLED EXACTLY TO THE ‘0’ MARK. TUBE SHOULD BE PLACED IN THE VERTICAL POSITION. ESR TO BE READ STRICTLY AFTER ONE HOUR.

SOURCES OF ERROR IF THE REAGENT CONCENTRATION IS HIGH,FALSE RESULTS WILL BE OBTAINED. TAKING THE HALF HOUR READING AND MULTIPLYING BY 2. WHEN THE SAMPLE IS NOT AT ROOM TEMPERATURE. TILTING OF THE WESTERGEN’S TUBE.

WINTROBE’S METHOD NOT THE PROCEDURE OF CHOICE. APPARATUS REQUIRED:WINTROBE TUBE. WINTROBE RACK. PASTEUR PIPETTE.

REAGENT USED:-

AMMONIUM POTASSIUM OXALATE.

PROCEDURE:-

BLOOD MIXED WITH THE REAGENT(2mg OF THE REAGENT /ml OF BLOOD). SUCK IT IN THE PIPETTE AND PUT INTO THE WINTROBE’S TUBE. TUBE IS THEN PLACED IN THE RACK. READ AT END OF 1 HOUR.

NORMAL RANGE WESTERGEN’S METHOD:MALES:-0-5 mm/Hr. FEMALES:-5-12 mm/Hr.

WINTROBE’S METHOD:MALES:- 0-9 mm/Hr. FEMALES:-0-20 mm/Hr.

ADVANTAGES WESTERGEN’S METHOD:SINCE THE TUBE IS LONGER THE VALUE OBTAINED IS MORE ACCURATE.

WINTROBE’S METHOD:ESR AS WELL AS PCV CAN BE MEASURED IN THE SAME SAMPLE.

DISADVANTAGES WESTERGEN’S METHOD:THE REAGENT USED CAN 1) DILUTE THE RBC’S AND INCREASE THE ESR. 2) DILUTE THE PLASMA FIBRINOGEN AND GLOBULIN,THEREBY DECREASING THE ESR.

WINTROBE’S METHOD:SINCE THE TUBE IS SHORTER AND THE SAMPLE VOLUME IS LESS,THE ACCURACY IS LOW.

PHYSIOLOGICAL VARIATIONS AGE:LOW IN INFANTS.INCREASES UPTO PUBERTY AND DECREASES TILL OLD AGE AFTER WHICH IT AGAIN INCREASES. SEX:GREATER IN FEMALES. PREGNANCY:INCREASES UPTO THE 3 rd MONTH AND THEN RETURNS TO NORMAL,ABOUT 3-4 WEEKS AFTER DELIVERY. ALTITUDE:ESR DECREASES AS THE ALTITUDE INCREASES. AFTER MEALS:ESR INCREASES.

PATHOLOGICAL INCREASE I. II. III. IV. V.

ALL INFECTIONS. ACUTE EPISODE OF CHRONIC INFECTIONS. ALL MALIGNANCIES. COLLAGEN DISEASES. ANAEMIA.

PATHOLOGICAL DECREASE POLYCYTHEMIA OF ANY ETIOLOGY. DECREASED LEVELS OF FIBRINOGEN. DISORDERS OF RBC SHAPE:FOR Eg:1. SICKLE CELL DISEASE. 2. HERIDETARY SPHEROCYTOSIS.

CLINICAL SIGNIFICANCE NOT A DIAGNOSTIC TEST. INDEX OF INFLAMMATORY ACTIVITY. GIVES CLUE REGARDING THE PROGRESS OF THE DISEASE AND ALSO THE RESPONSE TO TREATMENT. SINCE IT IS NORMAL IN FUNCTIONAL DISORDERS IT CAN BE USED TO RULE OUT ORGANIC DISEASES.