Hematocrit Determination Quiz

Hematocrit Overview

• Another term for hematocrit is packed cell volume (PCV).
• Hematocrit is reported in percentage (%).
• Main advantage of hematocrit determination over RBC count is providing a quick assessment of blood's capacity to carry oxygen, which reflects the overall blood volume.

Adam's Microhematocrit Method

• Materials NOT used in the Adam's microhematocrit method include sodium citrate as an anticoagulant.
• Sealing one end of the capillary tube with sealing clay prevents blood leakage and minimizes sample contamination.
• Blood is centrifuged at a speed of around 10,000 to 12,000 RPM in the microhematocrit method.
• A heparinized (red) capillary tube is used when the blood sample is not mixed with other anticoagulants or when a heparin anticoagulation is preferred.
• The volume of blood filled in the capillary tube in the Adam's microhematocrit method is typically approximately 75-100 mm.

Objectives and Calculations

• Objective of hematocrit determination includes analyzing anemia and assessing overall red blood cell mass.
• From the values of RBC count, hemoglobin level, and hematocrit level, mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC) can be computed.

Blood Smear Preparation

• Alternative name for cell volume percent (CV%) is hematocrit.
• Purpose of preparing a blood smear is to examine cell morphology and diagnose conditions such as infections and anemia.
• Ideal thickness of a blood smear is thin enough to see individual cells; achieved by rapid spreading with a slide.
• Common errors during blood smear preparation include thick smears or insufficient spreading; minimize by ensuring proper technique and angle.

Anticoagulant Influence

• Choice of anticoagulant affects blood smear quality; EDTA is most commonly used as it preserves morphology, important for accurate diagnosis.

Quality Control Measures

• Quality control measures for blood smear preparation include calibration of equipment, using the same anticoagulant consistently, and training personnel.
• The most appropriate specimen for smear preparation is fresh, anticoagulated capillary blood.

Methods of Preparation

• The Two-slide or Wedge method involves one slide for the smear and another as the spreader slide.
• The spreader slide should be positioned at an angle of approximately 30-45° in the Two-slide method.
• A characteristic of a good smear includes a feathered edge allowing for optimal cell evaluation.
• The method utilizing two cover glasses for smear preparation is called the Two-Cover Slip method.
• Main advantage of the Two-Cover Slip method over the Two-slide method is that it provides consistent thickness and minimizes air exposure.
• The coverage of the smear on the slide should be about one-half to two-thirds of the slide according to good smear criteria.
• Purpose of using anticoagulated blood for smear preparation is to prevent clotting and ensure uniform cell distribution throughout the smear.
• Main objective of smear preparation is to visualize blood cells effectively for diagnostic purposes.
• Good smear characteristics include being uniform, covering the slide adequately, and showing a clear separation of cells.
• The most popular method of smear preparation is the Wedge method.