ESR Procedure - Lecture notes ESR proccess PDF

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Erythrocyte Sedimentation Rate Erythrocyte Sedimentation Rate The erythrocyte sedimentation rate (ESR) is a simple and inexpensive laboratory test. It is commonly used toassess the acute phase of the inflammatory response and to help diagnose conditions associated with acuteand chronic inflammation, including infections, cancers, and autoimmune diseases. The ESR is nonspecific because the location of the inflammation cannot be assessed from the test, and the ESR can be affected by other conditions besides inflammation. For this reason, ESRis typically used in conjunction with other tests. Principle: Well-mixed venous blood is placed in a vertical tube. The red blood cells will settle out of the plasma and fall towards the bottom of the tube. After 60 minutes, measurements are taken of the distance the red cells have traveled.The length the RBCs have settled in the 60 minute time interval is the erythrocyte sedimentation rate. The ESR can be affected by two major factors, the red cell surface charges and the frictional forces around the red cell.Normally, the RBCs have a net negative charge and will repel each other. Abnormal proteins, such as excess fibrinogen or immunoglobulins, are often made in many disease states. These abnormal proteins cause the red cells to move closer together, allowing for the formation of rouleaux.When the RBCs are in a group like they are in rouleaux, they are heavier and fall faster. The faster they fall, thefurther they settle, and the higher the ESR. Fibrinogen,the most abundant acute phase reactant, has the greatest effect on the elevation of ESR when compared withother acute phase proteins. Paraproteins, positively charged molecules present in high numbers in multiple myeloma or Waldenstrom’smacroglobulinemia, will also increase the ESR levels by enhancing rouleauxformation as well as elevating plasma viscosity. The ESR is directly proportional to the RBC mass and inversely proportional to plasma viscosity. Patient physiological factors that affect the ESR include RBC size, RBC shape, plasma fibrinogen, and plasma viscosity. The sedimentation of the red cells takes place in three stages:  First stage “Aggregation Stage” – (occurring in the first 10 minutes) rouleaux formation begins. The sedimentation rate is very low  Second stage “Sedimentation stage” – (occurring in the next 40 minutes of the test) sedimentation occurs at a rapid rate. Most of the settling takes place during this stage.  Third Stage “Packing stage”– (occurring in the final 10 minutes of the test) sedimentation is slow due to the accumulation and overcrowding of the RBCs in the bottom of the tube. The packing of cells occurs in this stage. Even though the ESR is nonspecific, it can still be used for the following reasons:  To screen for certain disease states  To differentiate among diseases with similar symptoms  To serve as an index for disease severity  To monitor the course of an existing disease  To monitor a patient’s response to a disease

ESR by the SediplastWestergren Method

Specimen:  Well-mixed EDTA blood Materials and Equipment:  Peach colored vial, prefilled with diluent  Transfer pipettes  Calibrated Westergren pipette  Sedimentation Pipette Rack Procedure: 1. Remove the stopper on the pre-filled peach colored vial. 2. Fill to the indicated line with whole blood. 3. Replace the stopper and invert several times to mix. 4. Insert the Westergren pipette through the peach colored stopper lid and push down until the pipette touches the bottom of the vial.The blood should flow up to the zero mark. 5. Place the pipette into the sedimentation pipette rack and let stand for 60 minutes at room temperature. 6. Document the results at the end of the incubation time.

Reference Values for the Westergren Method:  Males 50 yrs: 0-20 mm/hr  Females 50 yrs: 030 mm/hr  Newborns: 0-2 mm/hr  Neonates to puberty: 3-13 mm/hr Sources of Error:  Air bubbles in the tube will interfere with accuracy  Tubes must be kept exactly vertical during testing  Test area must be free of vibrations (avoid centrifuges or other equipment)  Test sample and testing area must be at room temperature 20-25°C  Test must be read promptly at one hour for accurate results

ESR by the Wintrobe’sMethod Specimen:  Well-mixed EDTA blood Materials and Equipment:  Wintrobe glass tube  Needle and 5 ml syringe  Wintrobe Tube Rack Procedure: 1. Mix the EDTA blood thoroughly. 2. Using the needle and syringe, draw up approximately 2 ml of whole blood.

3. Slowly, as to not create bubbles, fill the Wintrobe tube up to the ‘0’ mark. 4. Place the tube into the Wintrobe Tube rack and let stand for 60 minutes at room temperature. 5. Document the results at the end of the incubation time. Reference Values for the Wintrobe Tube Method:  Males: 0-9 mm/hr  Females: 0-20 mm/hr

Causes of Increased ESRs:  All types of anemia except sickle cell  Macrocytosis  Elevated fifbrinogen  Excess plasma immunoglobulins – Multiple Myeloma  Acute and chronic inflammatory conditions and infections including: o HIV o Tuberculosis o Acute viral hepatitis o Arthritis o Bacterial endocarditis o Pelvic Inflammatory Disease o Ruptured Ectopic pregnancy o Systemic lupus erythematosus  African trypanosomiasis  Visceral leishmaniassis  Lymphoma, Hodgkins, disease, and some tumors  Some drugs including oral contrceptives Causes of Decreased ESRs:  Polycythemia  Microcytosis  Spherocytosis  Poikilocytosis  Newborns  Dehydration  Dengue Hemorrhagic fever...