MICROHEMATOCRIT DETERMINATION. D. 3.1. PRINCIPLE: When anticoagulated whole blood is centrifuged, the space occupied by the packed red blood cells is defined as the hematocrit (HCT), and is expressed as the percent of red blood cells in a volume of whole blood.
Table of Contents
Why is it important to read the Microhematocrit soon after the centrifuge stops?
Why is it important to read the microhematocrit soon after the centrifuge stops? RBCs being to settle out, causing falsely high results. How does hemolysis affect the microhematocrit? RBC contents lyse out back into plasma, causing falsely low results.
What is the purpose of the Microhematocrit?
Microhematocrit centrifuges are used for determination of volume fractions of erythrocytes (red blood cells) in blood and for separation of micro volumes of blood and solutions. It provides hematocrit values (HCT) for testing in biochemistry, immunity, genetics, blood separation and for general clinical tests.
How many minutes should the Microhematocrit be spinned?
For the microhematocrit method, after filling the blood in a capillary tube, the two ends of the tube (commonly 75 mm long, 1 mm diameter) are sealed with clay sealant or heat. Then, it is centrifuged at a rate of 11000 to 12000 rpm for 4 to 5 min.
What are the sources of error in hematocrit determination?
determination as ordinarily carried out, two main sources of error have been found, namely, errors in reading the haematocrit tube, and errors through failing to achieve uniform and adequate packing of the red cells.
What is the principle of haematocrit?
Principle of hematocrit (Hct) The word hematocrit means to separate the blood where the plasma and blood cells are separated. This test gives information about RBC concentration and is helpful to see hemoconcentration. This is basically a measurement of total blood volume and RBCs ratio as a percentage.
What precaution should be observed when performing a Microhematocrit?
What safety precautions should be observed when performing a microhematocrit? Observe Standard precautions; use plastic or Mylar-coated self-sealing tubes; close centrifuge lids securely; never open centrifuge until rotor has stopped; dispose of all sharps in appropriate containers.
What factors affect hematocrit levels?
- Living at a high altitude.
- Pregnancy.
- Significant recent blood loss.
- Recent blood transfusion.
- Severe dehydration.
What is the purpose of measuring the hematocrit percentage after centrifuge?
The hematocrit test measures the percentage of RBCs by volume in a blood sample. Because the purpose of red blood cells is to transfer oxygen from the lungs to body tissues, a blood sample’s hematocrit can become a point of reference for its capability of delivering oxygen.
How do you test for Microhematocrit?
How do you calculate hematocrit?
Hematocrit is the packed spun volume of whole blood that is made up of RBCs and is expressed as a percentage of total blood volume. It can be measured or calculated as Hct = (RBC × MCV)/10.
How do you calculate hematocrit from capillary tube?
Hematocrit is estimated by calculating the ratio of the column of packed erythrocytes to the total length of the sample in the capillary tube, measured with a graphic reading device. The measurement should be performed within 10 minutes to avoid merging of the layers.
At what speed does a hematocrit operate?
The speed of haematocrit centrifuges ranges from 7000 to 15000 rpm. The haematocrit centrifuge can hold up to 24 capillary tubes of size 1.2 mm × 75 mm.
What are the advantages of Microhematocrit method?
Advantages of the Microhematocrit Method The amount of trapped plasma is less than that in the Wintrobe method by virtue of the higher centrifugation speed employed.
Is hematocrit always 3 times hemoglobin?
Hematocrit will always be three times the hemoglobin value, regardless patient’s hydration status. For example, if a patient has a hemoglobin value of 12.0 g/dL, he should have a 36% hematocrit. If he is overhydrated, his hematocrit will decrease, also his hemoglobin.
Do air or bubbles affect the the measurement of hematocrit using micro method?
The results showed that the passage of air bubbles strongly influences the cell’s local concentration, since a higher concentration of cells was observed upstream of the bubble, whereas a lower local hematocrit was visualized at the region downstream of the bubble.
What are the methods of measurement and related indices of hematocrit?
The volume of packed red blood cells divided by the total volume of the blood sample gives the PCV. Since a tube is used, this can be calculated by measuring the lengths of the layers. Another way of measuring hematocrit levels is by optical methods such as spectrophotometry.
What can cause high hematocrit?
- Bone marrow disease that causes abnormal increase in red blood cells (polycythemia vera)
- Congenital heart disease.
- Exposure to high altitude.
- Failure of the right side of the heart.
- Low levels of oxygen in the blood.
- Scarring or thickening of the lungs.
What technical factors can affect the quality of Microhematocrit results?
What technical factors can affect the quality of microhematocrit results? The centrifuge speed and time directly affect the microhematocrit values—failure to spin tubes at the correct speed and for the correct time can cause erroneous results.
What units is hematocrit measured in?
Hematocrit is a measure of the portion of blood occupied by cells (red blood cells, white blood cells and platelets). A hematocrit of 0.40 L/L (litre of cells per litre of blood) indicates that 40% of the blood volume is composed of cells, with plasma making up the other 60%.
What is the importance of centrifuging a Microhematocrit tube?
When centrifuging a microhematocrit tube, it is important to: Plug one end of the tube with clay. What instrument would the technician use to measure both the urine specific gravity and the protein levels of blood?
How do you fill a Microhematocrit tube?
Hold the tube at an angle and introduce the microhaematocrit (capillary) tube. Allow blood to track up the tube. Continue until the tube is about 3/4 full. Put your index finger over the top of the capillary tube before removing it from the sample or blood will leak!
How is a capillary tube sealed when performing a Microhematocrit?
Heparinized blood is transferred from the microcentrifuge tube (often called eppendorf tube) to a microhematocrit capillary. The tube is filled to at about 3/4 capacity by capillary action. Then the blood-filled end is sealed with clay, and placed in a slot in the hematocrit centrifuge.
What increases and decreases hematocrit?
An increased hematocrit may be due to dehydration or polycythemia. Decreased values may be due to anemia, over hydration, kidney failure, or chronic inflammatory conditions. Pregnancy may also cause slightly decreased hematocrit due to an increase in blood volume.
How does age affect hematocrit levels?
As the dis- tribution shifts to the left or toward lower values with increasing age as it does for men, the mean hematocrit decreases. As the distribution shifts to the right or toward higher values with age, as it does for women until ages 55-64 years, the mean increases.