ESR HEMA LAB PDF

ERYTHROCYTE SEDIMENTATION RATE Prepared by: Monique G. Lago, RMT INTRODUCTION ERYTHROCYTE SEDIMENTATION RATE is a nonspecific measurement used to detect and monitor an inflammatory response to tissue injury. It primarily reflects changes in the plasma proteins that accompany most a...

ERYTHROCYTE SEDIMENTATION RATE Prepared by: Monique G. Lago, RMT INTRODUCTION ERYTHROCYTE SEDIMENTATION RATE is a nonspecific measurement used to detect and monitor an inflammatory response to tissue injury. It primarily reflects changes in the plasma proteins that accompany most acute and chronic infections, tumors, and degenerative diseases. PRINCIPLE ESR is the rate of settling of RBC in anticoagulated blood measured through the distance travelled by the RBCs in one hour. STAGES OF ESR 1. LAG / 3. FINAL SETTLING AGGLOMERATION PHASE PHASE Initial, about 10 mins 10 mins Rouleaux formation Further packing Slower rate of fall 2. DECANTATION PHASE Appx 40 mins Constant sedimentation Rapid packing of RBCs The longer the tube, the longer stage 2 will last, there fore the higher the ESR result FACTORS THAT INFLUENCE ESR ERYTHROCYTES Rouleaux formation of RBCs RBCs are negatively charged and therefore repel each other. In cases of inflammatory response and certain diseases, plasma protein concentrations may be altered, causing a reduction in negative charge of RBCs and consequent formation of rouleaux. This leads to a larger mass and increased sedimentation velocity. Agglutination of RBCs Agglutination due to changes in RBC surface also leads to increased rbc mass and more rapid sedimentation rate. FACTORS THAT INFLUENCE ESR ERYTHROCYTES Size or mass of RBCS: the larger the size, the faster its rate Macrocytes = inc Microcytes = dec Anisocytosis = dec Shape of RBCS = changes in rbc shape tend to reduce the ability of rbcs to form large aggregates Poikilocytes = dec Anemia = inc The conc of rbcs in blood is dec, with the hematocrit reduced, the velocity of the upward flow of plasma is altered so that red blood cell aggregates fall faster Polycythemia = dec The blood is viscous and too many red blood cells decrease the compactness of the rouleau network FACTORS THAT INFLUENCE ESR PLASMA COMPOSITION Viscosity of plasma As the concentration of protein increases so does the viscosity of plasma. Increased plasma viscosity will tend to inhibit the fall of rbcs Acute phase proteins Rouleaux and aggregation of RBCs are controlled primarily by the levels of acute phase proteins, increasing as these are increases in plasma. Increased plasma proteins affect the ESR more greatly than does the increased plasma viscosity. FACTORS THAT INFLUENCE ESR PLASMA COMPOSITION Fibrinogen = inc Alpha 1 globulin = inc Alpha 2 globulin = inc Albumin = dec FACTORS THAT INFLUENCE ESR MECHANICAL / TECHNICAL FACTORS Tilting of tube = inc Increased temperature = inc Vibration = inc Length and diameter of tube = inc METHODS OF ESR WINTROBE AND LANDSBERG Tube length: 11cm, Bore: 3 mm Anticoagulant: EDTA, Double oxalate Wintrobe tube can also be used for Hematocrit determination ORIGINAL WESTERGREN Tube length: 30 cm, Bore 2.5 mm Anticoagulant: Sodium citrate MODIFIED WESTERGREN Anticoagulant: EDTA 2ml EDTA blood is diluted with 0.5 ml 0.85% NSS or 3.8% Sodium citrate Undiluted blood = poor precision WESTERGREN TUBE VS. WINTROBE TUBE WINTROBE METHOD OF ESR 1. Fill up tube with oxalated or EDTA blood up to 0 mark using Pasteur pipette with long stem 2. Avoid bubble formation, tilting of tube, sunlight, and vibration 3. Allow to stand in vertical position for 1 hour 4. Read and record the result in mm/hr. When Hematocrit is done alongside ESR: After reading ESR after 1 hr, centrifuge the tube for 15 mins for Hct result WINTROBE METHOD OF ESR WESTERGREN METHOD OF ESR 1. Mix and draw whole blood (4 volumes) with 0.109M TSC (1 volume) up to 0 mark 2. Avoid bubble formation, tilting of tube, sunlight, and vibration 3. Allow to stand in vertical position for 1 hour 4. Read and record the result in mm/hr. NOTE: MODIFIED WESTERGEN If EDTA is used, dilute 2 ml blood with either 0.5 ml 3.8% Na Citrate or with 0.5 ml 0.85% NaCl WESTERGREN METHOD OF ESR REFERENCE VALUES WESTERGREN WINTROBE METHOD METHOD Male = 0-9 mm/hr Male Female = 0-20 mm/hr 50 y/o = 0-20 mm/hr Female 50 y/o = 0-30 mm/hr Children = 0-10 mm WESTERGREN VS. WINTROBE Westergren is the most sensitive of the methods, because of the longer tube that requires more blood One advantage of this method is that the taller column height allows the detection of highly elevated ESRs. Westergren method has been chosen as the standard method by Intl Committee for Standardization in Hematology Wintrobe requires a smaller amount of blood and involves no dilution. The shorter column height allows a somewhat increased sensitivity in detecting mildly elevated ESRs SOURCES OF ERROR If the concentration of EDTA is greater than recommended, the ESR will be falsely low. The anticoagulants sodium or potassium oxalate and heparin cause the red blood cells to shrink and falsely elevate the ESR. If the ESR stands for more than 60 minutes, the results will be falsely elevated, and vice versa A marked increase in room temp leads to increased ESR, and vice versa Tilting of ESR tube increases sedimentation rate Bubbles in the blood cause invalid results Fibrin clots present in the blood invalidate the test results SOURCES OF ERROR Increased reticulocytes may cause poor separation of rbcs and plasma layer = “Stratified sedimentation” Blood specimens must be analyzed within 4 hours of collection if kept at room temperature (18 to 25° C).15 If the specimen is allowed to sit at room temperature for more than 4 hours, the red blood cells start to become spherical, which may inhibit the formation of rouleaux. Blood specimens may be stored at 4° C up to 24 hours prior to testing, but must be rewarmed by holding the specimen at ambient room temperature for at least 15 minutes prior to testing. The blood must be filled properly to the zero mark at the beginning of the test. INCREASED AND DECREASED ESR ELEVATED DECREASED Pregnancy Polycythemia Menstruation Congestive heart failure Acute and Chronic infections Rheumatic fever Hypofibroginemia Rheumatic arthritis Presence of RBC Nephrosis abnormalities TB (Poikilocytosis, Macroglobulinemia Spherocytes, Sickle Cryoglibulinemia cells) Rodak’s Chapter 14, page 201: TABLE 14-3 Factors Affecting the Erythrocyte Sedimentation Rate (ESR) OTHER METHODS OF ESR DETERMINATION MACROMETHODS 1. GRAPHIC OR CUTLER Anticoagulant of choice is 3% sodium citrate Uses Cutler tube which as a 5ml capacity; graduation of 0-50 mm Tube is allowed to stand for 1 hr, observing every 5 minutes Normal values: Male: 0-8mm/hr (Average: 3-5 mm/hr) Female: 0-10 mm/hr (Average: 5-6 mm/hr) During menstruation: 12 mm/hr OTHER METHODS OF ESR DETERMINATION MACROMETHODS 2. LINZENMEIER METHOD Anticoagulant of choice is 3% sodium citrate Uses Linzenmeier tube which is 65 mm in length, 5 mm in diameter, and has a capacity of 1 ml (with a a mark at 18mm) The tube is allowed to stand in an upright position until the rbcs settle at the 18 mm mark Normal values: Male: 350-600 minutes Female: 300-600 minutes During menstruation: 600 minutes OTHER METHODS OF ESR DETERMINATION MACROMETHODS 2. BRAY’S METHOD Anticoagulant of choice is 1.3% sodium citrate It uses Bray’s tube which is flat-bottomed and calibrated on both sides like the Wintrobe tube Bray’s tube can also be used for Hematocrit and LE preparation The tube is set vertically, and the rate of settling is read every five minutes for 30 minutes and the total fall after one hour. Then a graph is plotted, and the maximum sedimentation rate is also recorded. It is usually sufficient to make readings at 10, 20, 30, and 60 minutes OTHER METHODS OF ESR DETERMINATION MICROMETHODS 1. MICRO LANDAU A modification of Linzenmeier-Raunert Anticoagulant of choice is 5% sodium citrate Is uses a Micro-Landau tube which is calibrated 0-50mm and has two graduation marks, one at 12.5 mm and another at 62.5 mm, with a small bulb similar to rbc and wbc pipettes 2. SMITH MICRO Used for infants and children when venipuncture may not be practical 3. CRISTA OR HELLIGE-VOLLMER OTHER METHODS OF ESR DETERMINATION AUTOMATED METHODS AUTOMATED ESR SYSTEM BY VEGA BIOMEDICAL The automated ESR system is a fully automated instrument for ESR dertermination. One ml of blood is collected on an evacuated tube containing liquid sodium citrate. The tube is then placed in the Ves-matic analyzer where it is automatically mixed, allowed to settle, and read. Results are comparable to the Westergren method. The determination takes only 2 minutes to finish. 1. MINI-VES – 4 samples at one time 2. VES-MATIC – 20 samples at one time; print results 3. VES-MATIC 60 – 60 samples at one time; print results; and identifies sample by a barcode reader