The document defines hematocrit as the volume of red blood cells (RBCs) relative to the total volume of whole blood, expressed as a percentage. It notes there are two methods for measuring hematocrit: the macrohematocrit and microhematocrit methods. Normal hematocrit ranges are provided for men, women, infants/children, and newborns. Factors that can increase or decrease hematocrit levels are outlined, and indications for estimating hematocrit are given as screening for anemia and calculating red blood cell indices.

1. Haematocrit / Packed cell volume (PCV)
• Def: PCV is the volume of RBC in relation to that
of whole blood.
• Hematocrit literally means blood separation.
• It expressed as the volume of red blood cells per
litre of whole blood.
• It may be also expressed as %.
Dr. SAYID

2. Haematocrit / Packed cell volume (PCV)
1. Macrohematocrit method (Wintrobe Method)
2. Microhematocrit method
Dr. SAYID

3. Components of Whole Blood
Withdraw blood
and place in tube
1 2 Centrifuge
Plasma
(55% of whole blood)
Formed
elements
WBC and platelets
(<1% of whole blood)
Erythrocytes
(45% of whole blood)
Dr. SAYID

4. Haematocrit –Normal value
Men
0.40 to 0.54 l/l (40 – 54%)
Women
0.37 to 0.47 l/l (37 – 47%)
Infant/child
0.30 to 0.43 l/l (30 - 43%)
Newborn
0.53 to 0.65 l/l (53 - 65%)
Dr. SAYID

5. High Hematocrit Level
Some factors may cause a rise in hematocrit value
such as:
• Polycythemia
• Heart or kidney problems
• Intake of anabolic steroids
• Dehydration
• Diarehea
• Lung problems
• Burns
• Smoking
• High altitudes Dr. SAYID

6. Low Hematocrit Levels
Low hemoglobin levels due to:
• Anemia
• Hemolysis
• Nutritional deficiencies
• Bleeding
• Pregnancy
Dr. SAYID

7. Indication of Hematocrit estimation
1. Screening test for anaemia
2. For calculation of red cell indices
Dr. SAYID