Hematocrit (HCT) or Packed Cell Volume (PCV)

● Hematocrit is the volume of packed red cells in a particular specimen of blood calculated as a percentage of total volume of blood.

● Hematocrit (HCT) and packed cell volume (PCV) are used to measure red blood cell mass.

● It is generally a part of the complete blood count (CBC) test.

● The PCV test measures how much of the blood consists of cells.

● Hematocrit may be measured by centrifugation or automated methods.

● A PCV of 40% means that there are 40 millilitres of cells in 100 millilitres of blood.

Hematocrit (HCT)

● A calculated value obtained from modern automated hematology analyzers.

● It is the product of the mean cell volume (MCV) and the red blood cell (RBC) count, both of which are directly measured by the analyzer.

● The formula used to calculate the HCT is as follows:

HCT = (MCV x RBC count)÷10

Packed cell volume (PCV)

● This is a directly measured value obtained from centrifuging blood in a micro-hematocrit tube in a micro-hematocrit centrifuge.

● The PCV is measured as the height of the red cell column in a micro-hematocrit tube after centrifugation.

● It is the quickest and most readily available measure of the red blood cell component of blood

Normal Ranges of Packed cell volume (PCV)

● Male adult: 42 – 52%

● Female adult: 35 - 47%

● Pregnant females: 33- 38%

● New born: 42- 64%

● 1 – 5 year: 31 - 44%

● 5 – 10 year: 35 – 44%

● 11 – 18 year: 37 – 48% (male), 34 – 44% (female)

Indications of Packed cell volume (PCV)

● Hematocrit shows that a patient has anemia, erythrocytosis, or changes in plasma volume.     

● Hematocrit value is used as a cutoff to determine the amount of requirement for transfusion.

Interpretation of Packed cell volume (PCV)

● Hematocrit is raised with an increase in the number of red blood cells or a decrease in plasma volume.

● Hematocrit falls in decreased erythropoiesis or hemolysis and hemorrhage where plasma volume is increased.

Increased Levels of Packed cell volume (PCV)

● Polycythemia vera

● Burns

● COPD

● Congenital heart disease

● Dehydration

● Eclampsia

Decreased Levels of Packed cell volume (PCV)

● Anemia

● Hemoglobinopathy

● Bone marrow failure

● Hemorrhage

● Hemolytic reaction

● Normal pregnancy

● Multiple myeloma

● Leukemia or lymphoma

● Nutritional deficiencies of iron or vitamin (B12 or folate) and mineral deficiencies

● Recent or long-term blood loss

Interfering Factors of Packed cell volume (PCV)

Altitude:People living in high altitudes have a high HCT.

Pregnancy: Hemodilution of pregnancy causes decreased HCT.

Age: Lower HCT is seen in men and women over the age of 60.

Dehydration: Severe dehydration causes a false increase in HCT.

Nursing Implications of Packed cell volume (PCV)

● Manage fatigue avoid complications of anemia, maintain adequate nutrition, maintain adequate perfusion, and encourage compliance with prescribed therapy.