Hematocrit.pdf

hematocrit THE PACKED CELL VOLUME (PCV) CAN BE Sealing wax & Microhematocrit centrifuge ESTIMATED VIA: 1.Macro-method (Wintrobe's method) 2. Micro-method (microhematocrit) MICROHEMATOCRIT METHOD §Principle: ~...

hematocrit THE PACKED CELL VOLUME (PCV) CAN BE Sealing wax & Microhematocrit centrifuge ESTIMATED VIA: 1.Macro-method (Wintrobe's method) 2. Micro-method (microhematocrit) MICROHEMATOCRIT METHOD §Principle: ~ Hematocrit is usually determined by spinning method using a blood -illed capillary tube in a centrifuge machine. §The coulter counter series of analyzers provide an indirect measurement of hematocrit. Materials (reagents & instruments): §Capillary tubes, plain (75 mm) §Microhematocrit centrifuge § Microhematocrit reader §Hematocrit tube sealant Procedure (sample): Hematocrit Centrifuge Capillary and venous blood in anticoagulated EDTA tube or directly collected and used blood Procedure (step-by-step): 1.Mix the anticoagulated venous or capillary blood gently 5 times. 2. Fill (2/3) the capillary tube with blood (prefer to use two tubes for each sample) 3.Seal one end of the tube with plasticine (sealing wax) and place these tubes in the microhematocrit centrifuge. 4.Centrifuge for 5 minutes at 10,000 rpm. 5. Place the tube in microhematocrit scale/ reader. 6.The bottom margin of red cells layer is against the O mark of the scale; While the top margin of plasma layer should be facing the 100 mark. 7. Now adjust the sliding line so that it cuts between the red cell layer and the buffy coat. 8. Note the reading. This is PCV (%)  hematocrit Microhematocrit scale/ reader Decrease Result can be seen in the following conditions §Anemia §Pregnancy Increase Result can be seen in the following conditions §Newborns §Burn patients §High altitudes §Dehydration NORMAL VALUES/ RANGE PRECAUTIONS Incomplete sealing of the capillary tubes will give falsely low results. Shortened spin time or slowed centrifugation speed may yield falsely elevated results. Microhematocrit centrifuge should never be forced to stop by applying pressure to the metal cover plate. The hematocrit is usually three times the hemoglobin Sources of Error §Incorrect anti-coagulant concentration. §Incorrect mixing. §Storage for 6-8 hours. §Incorrect centrifugation. §Hemolysis. §Clots in the blood sample.