Hematocrit Test PDF

5/22/2023 By Abdulfatah albakkosh Practical hematology Hematocrit (Hct) OR packed cell volume ( PCV) • Hematocrit or PCV is the percentage of red blood cells in the total blood volume. Hematocrit Determination : The two methods currently used for direct measurement of PCV are : 1. Macro –method...

5/22/2023 By Abdulfatah albakkosh Practical hematology Hematocrit (Hct) OR packed cell volume ( PCV) • Hematocrit or PCV is the percentage of red blood cells in the total blood volume. Hematocrit Determination : The two methods currently used for direct measurement of PCV are : 1. Macro –method : using Wintrobe tubes 2. Micro –method : using capillary tubes The Micro–method is more popular because : a With this method, centrifugation lasts less time. b) it results in better red cell packing 1 5/22/2023 Micro –Hematocrit Method • This method requires small amount of blood, 2 to 3 drops . Requirement • 1- Blood sample : Venous blood or capillary blood tubes (blood from a finger puncture may be used) that are anticoagulated 2- capillary tubes : use capillary tubes for anticoagulated venous blood and use heparinised capillary tubes for blood obtained from finger puncture. • The capillary tubes 75 mm in long . 5/22/2023 Heparinized tubes are red coded, and non-heparinized are blue coded. 3- Micro hematocrit centrifuge : 3- Micro hematocrit centrifuge : this is a special type of centrifuge. The top of the centrifuge is grooved and flat. It has a speed of around 15,000 RPM. The timer is often set for five minutes. 4- Hematocrit Reader. 5. Clay is used to cover the capillary tube end. 5/22/2023 Clay Micro centrifuge Hematocrit Reader Hematocrit Reader 5/22/2023 Procedure • Samples of blood should be as fresh as possible and well mixed. • The blood flow should be free and low-pressure. • The capillary tube was filled to a length of 75%, and its other end was closed with clay or wax. • Place two Hct tubes in the opposing grooves of the centrifuge. • Five minutes of centrifugation at a speed of 13,000+ 2,000 rpm. 5/22/2023 The read with card reader : • The reader is used to hold the tube against the scale so that the bottom of The red cell corresponds to the card's O (zero) line. • Move the tube across the card until the uppermost line of plasma is matched to 100% of card. • The tube should be straight and vertical. • The line that passes through The HCT value is given by the HCT value at the top of the RBC column. 5/22/2023