Hematology Lab - 07 Erythrocyte Sedimentation Rate

HEMATOLOGY LABORATORY ERYTHROCYTE SEDIMENTATION RATE ERYTHROCYTE SEDIMENTATION RATE (ESR) • Aka Sed Rate • The distance in millimeter (mm) at which RBCs fall in 1 hour • A non-specific marker of underlying inflammation • Reporting : mm/hr MATERIALS • EDTA Whole Blood (min. of 2 mL) • Wintrobe tube • Wintrobe tube stand • Westergren tube • Westergren tube stand • Long-tipped Pasteur pipette - for Wintrobe Methods • Rubber Aspirator (for glass pipette) • NSS (0.85% NaCl Solution) - for Westergren Methods o Strength can affect result WINTROBE-LANDSBERG METHOD • Modification of Wintrobe method • Uses Wintrobe Tube : o Bore : 3.0 mm (internal diameter) o Calibrations : up to 100 mm (10 cm) ▪ White – Macrohematocrit reading (10 → 0) ▪ Red – ESR reading (0 → 10) o Length : 115mm • Specimen : o EDTA whole blood o Citrated Blood (3.8% Na citrate - black) • Procedure : 1. Fill up the wintrobe tube to the 0 mark with EDTA whole blood/oxalated blood using long-tipped Pasteur pipette ▪ Bubbles can affect ESR result; reject and repeat when present 2. Allow to stand in a vertical position for one hour at room temperature 3. Take and record reading in mm/hr ▪ Do not include buffy coat WESTERGREN METHOD • More commonly used ESR method • Uses Westergren Tube : o Bore : 2.5 mm o Calibration : 200 mm o Length : 300 mm • Specimen : o Citrated Whole Blood (3.8% Na citrate - black top) o EDTA whole blood ▪ Diluent : 3.8% Na Citrate or NSS ▪ Dilution : 4 parts blood to 1 part diluent • 0.4 mL diluent and 1.6 mL blood • Procedure : 1. Mix blood by gentle inversion 2. Insert Westergren tube into the tube containing blood ▪ Has stopper at top allowing exact volume 3. Allow to stand in a vertical position for one hour 4. Take and record reading in mm/hr (do not include buffy coat, may cause false ↑) • Reference Values: 0-50 y.o. >50 y.o. Men 0 - 15 mm/hr 0 - 20 mm/hr Women 0 - 20 mm/hr 0 - 30 mm/hr o ESR Value of men are more constant than women ▪ During pregnancy, ESR can increase esp. during 3 rd -4 th trimester; ESR normalize after birth STAGES OF ESR 1. Agglomeration Phase/Lag Phase (10 minutes) o Initial rouleaux formation occurs o Few cells sink under gravity but majority form agglomerates 2. Rapid/Fast Settling Phase (40 minutes) o aka Decantation phase o More rapid and constant RBC sedimentation ▪ Due to heavier RBC from agglomerates 3. Final Sedimentation Phase (10 minutes) o aka Final Settling Phase o RBC sedimentation is slow o Majority of RBCs are settled CLINICAL SIGNIFICANCE • High ESR o Rheumatoid arthritis o Lupus o Anemia o Endocarditis o Kidney disease o Osteomyelitis o Tuberculosis o Syphilis o Thyroid disease • Low ESR o Sickle cell anemia o Polycythemia o Blood hyperviscosity o Hypofibrinogenemia o Congestive heart failure FACTORS AFFECTING ESR Factors Effects Notes Old Specimen (>4hrs) ↓ ESR Room temp: Within 4 hours Refrigerator: Within 24 hours Plasma Proteins All Plasma Proteins: ↑ ESR Albumin: ↓ ESR Sickle Cell and Spherocytes ↓ ESR Prevents rouleaux formation Plasma viscosity More viscous: ↓ ESR Less viscous: ↑ ESR

Factors Effects Notes Temperature (Optimal: 22-27C) <22C: ↓ ESR >27C: ↑ ESR Inclination ↑ ESR Tilt (3°) – up to 30% error Bubbles ↓ ESR Repeat when present Anticoagulant concentration Increased AC conc: ↓ ESR Increase AC result to sphering of RBC Vibration ↑ ESR Pregnancy ↑ ESR 3rd or 4th trimester - 3rd /4th week after birth Thalassemia ↓ ESR • For refrigerated specimens, prewarm samples for 15 minutes before testing o Failure to prewarm can cause erroneous • >4hrs - RBCs become spherical preventing rouleaux o Rouleaux is important for 1 st stage • Increased AC conc. - means short draw (insufficient blood)