Test DescriptionHematocrit is defined as the proportion of red blood cells to plasma within a sample of blood. Following collection of the sample, the specimen is centrifuged. Due to their weight, the red blood cells are forced to the bottom of the test tube. A determination of the percentage of these packed cells in comparison to the plasma is then made. Hematocrit can be used to assess the extent of a patient’s blood loss. A drop of 30% in hematocrit equals approximately one unit of blood loss. It is important to note, however, that the drop in hematocrit does not occur immediately. As a result of a large blood loss, there is a loss of equal proportions of red blood cells and plasma. Thus the hematocrit remains normal for a period of time. Hematocrit is the percentage of red blood cells in a volume of whole blood.
In an attempt to compensate for the blood loss and return the plasma volume to normal, the body shifts fluid from the intracellular and interstitial compartments to the intravascular compartment. Red blood cells, however, are not able to be replaced in such a short time. Thus, the relative percentage of red blood cells, as denoted by the hematocrit, will decrease. Hematocrit is a useful measure only if the patient’s hydration level is normal . When normal hydration is present and the total red blood cell count and hemoglobin are both normal, the hematocrit is approximately three times the hemoglobin result.
Females
Adult38%–48% Pregnant
37%–46% Adult Males
40%–52% Children
Neonates
40%–68% 3 months29%–54% 1–2 years 35%–44% 6–10 years 31%–45% Panic Levels
<15% or >60%
Increased Burns Cardiovascular disease Chronic lung disease Erythrocytosis Congenital heart defect Dehydration(hemoconcentration) Hepatic cancer Polycythemia vera Renal cyst
Decreased Anemia Bone marrow suppression Chronic infection Hypothyroidism Malnutrition Multiple myeloma Over hydration (hemodilution) Pregnancy Renal disease Rheumatic fever
1- Heparinized tube (capillary tube are about 75 mm in length) are used for capillary blood and none –heparinized tube for venous EDTA anticoagulant blood .2-microhematocrite centrifuge capable of reaching maximum speed with in 30 seconds.3-Hematocrite reader .4- Artificial clay.
1- the none heparinized tube filled with EDTA anti coagulated blood ,or the heparinized tube filled with capillary blood(ensure that there is no air bubbles ) . The empty end is sealed by artificial clay or heating rapidly in fine flame . 2- the sealed tube is placed in special microhematocrite centrifuge with sealed ends to word the out side of special tube holder and are centrifuged for 5 minutes at3500 rpm . 3- after centrifugation the result read with specific reading the blood separated into : A- column of red cells at bottom B- a narrow middle zone of Buffy coat consists of WBC and platelets C- plasma fluid
Fill the tube till the 100 mark and centrifuge the tube for 15 minutes at 3500 rpm ,after centrifugation the blood is separated in to 3 layers : A- column of red cells at bottom B- a narrow middle zone of Buffy coat consists of WBC and platelets C- plasma fluid