| Blood Laboratory | Blood cell indices > RBC count | ||||
| Among the most common hematological tests performed are those which determine the red blood cell count, the hematocrit, the hemoglobin content, ABO/Rh Blood Group typing, and the total and differential white blood cell count. Each one of these measurements may be carried out on a single drop of blood. | |||||
| Review the topics in your textbook. | |||||
| Theory | |||||
| A convenient and inexpensive way to count blood cells is through the use of the hemocytometer. This instrument is a special microscope slide on which precise grids have been etched within a counting chamber designed to hold an exact volume of diluted blood sample. The blood cell determination involves counting cells in several squares of the grid and obtaining an average number. That number is multiplied by a factor that compensates for the amount of dilution. The final result expresses the number of red blood cells per cubic millimeter of the original blood sample.
The picture above shows a hemocytometer, on top of which a coverslip (thin square glass slide) was placed to delimit the area of each of the counting chambers, top and bottom. The groove (present on some hemocytometer models) on the edge of each counting chamber facilitates the positioning of the pipette tip and the loading of the diluted blood sample. | |||||
| Procedure | |||||
 The picture above shows a microcentrifuge tube (sometimes referred to as an eppendorf tube) containing the diluted blood sample in Gower's solution, a 20 ml adjustable pipette (or pipetman) and the hemocytometer. | In order to be able to effectively count cells, venous blood in EDTA (as anticoagulant) must be added to an isotonic solution (Gower's solution) which prevents lysis and crenation of erythrocytes. Gower's solution also contains a fixative which acts as a preservative and prevents agglutination of cells if counting cannot be done within an hour. Preparation of the diluted blood sample:Volume to volume dilution is one in which a unit volume of a solute is combined with an appropriate volume of a solvent liquid to achieve the desired concentration. The dilution factor is the total number of unit volumes in which the solute is dissolved in the solvent. This dilution factor method is based on ratios. Loading the hemocytometer: After adequate mixing, the diluted blood is introduced into the counting chamber where the cell count is performed microscopically. | ||||
Caution:
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 The 20 ml pipette tip is placed on the hemocytometer at the edge of the coverslip. The plunger of the adjustable pipette is slowly pressed so that the sample flows between the hemocytometer's raised shiny surface and the coverslip. Stop when the sample touches the three sides of the chamber (about 10 ml); do not overflow into the moat which surrounds the chambers. | |||||
| Counting | |||||
| Observe the grid of the hemocytometer below. Different areas are used for counting red blood cells and white blood cells. Red cells are counted in the areas indicated in red. | |||||
| Consider the following: The central grid of 25 squares is 1mm x 1mm in area and 0.10 mm deep, and holds 0.1ml of liquid. The dilution factor is 1:200. Convert the number of red blood cells that are counted in 5 squares to the number of red blood cells/µl. (N.B. 1 µl (microliter) = 1 cubic mm ). Since only 5 out of the 25 squares (1:5) are counted, you must multiply your count by 5. | |||||
 | Click here to open a window which mimics what you might see looking through the 40x objective of a microscope. Only the center of the grid shown above is visible (where the 5 squares are coloured red). Try to verify this by observing the fineness of the grid as you move to the edges of the visible field. Count the red cells in the five squares and determine the red cell count as described above. Important note: To avoid counting the same cells twice, cells that are touching the lines at the tops and left sides of the squares are counted, but cells that are touching the bottoms and right sides of the squares are not counted.
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FAQs
What do blood cell indices mean? ›
Red blood cell (RBC) indices are part of the complete blood count (CBC) test. They are used to help diagnose the cause of anemia, a condition in which there are too few red blood cells. The indices include: Average red blood cell size (MCV) Hemoglobin amount per red blood cell (MCH)
Which blood indices is most reliable? ›The MCV is the most useful value in the RBC indices to help determine the type of anemia you may have. Your doctor will see if your MCV is low, normal, or high to help determine what is causing your anemia.
What causes low red cell indices? ›A low RBC count is often caused by blood loss or by inadequate RBC production, often due to low iron. It can also be caused by kidney disease, dehydration, and various other diseases.
What does low MCV, MCH, mchc, and high rdw mean? ›For example, low MCV, MCH, and MCHC strengthen the evidence of anemia, as they are all influenced by hemoglobin concentration. MCHC should not fall under its normal range of 32 to 36 (d/dL). On the other hand, RDW lab values tend to increase in the presence of anemia.
What is the biggest symptom of anemia? ›If you have anemia, your body does not get enough oxygen-rich blood. The lack of oxygen can make you feel tired or weak. You may also have shortness of breath, dizziness, headaches, or an irregular heartbeat.
What level of MCV is concerning? ›An MCV test measures the size and volume of red blood cells. A normal MCV range is roughly 80–100 fl . If someone's MCV level is below 80 fl, they will likely develop or have microcytic anemia. Alternatively, if their MCV levels are greater than 100 fl, they could experience macrocytic anemia.
What does it mean when your MCV and MCH are high? ›Most elevated MCV reports are accompanied by an elevated mean corpuscular hemoglobin (MCH). Elevation of MCV and/or MCH suggests macrocytosis. This activity reviews the evaluation and treatment of macrocytosis and highlights the role of the healthcare team in the care of patients with this condition.
Is a high RBC count good or bad? ›What does it mean when your red blood cell count is high? If you have a high red blood cell count, then you have something called erythrocytosis. This makes your blood thicker than it should be, and it could increase your risk for blood clots.
What is a normal red blood cell count? ›For adults, the usual range is generally 4.35 to 5.65 million red blood cells per microliter (mcL) of blood for men and 3.92 to 5.13 million red blood cells per mcL of blood for women. In children, what's thought of as high depends on age and sex.
What drink increases red blood cells? ›Iron-rich drinks include apple juice, apricot nectar, beef broth, beet juice, cocoa using natural cocoa powder, “green” smoothies, orange juice, pea protein smoothies, prune juice, tomato juice, and spinach juice.
How do you increase red cell indices? ›
Iron is the key element in increasing Red Blood Cell Count. You need to include some iron-rich foods like pork liver, mutton, shrimp, fish, oats, muesli, spinach, chickpeas, cabbage, beetroot, and pistachios in your diet to elevate your Red Blood Cell Count.
What does anemia fatigue feel like? ›Fatigue. Tiring easily, and waking up tired even after a good night's sleep, are common and potentially serious symptoms of anemia. This is due to reduced and compromised red blood cells that naturally cannot carry the required levels of oxygen to the organs – which, in turn, cannot function efficiently.
Is it better to have high or low RDW? ›Additionally, in 2019 , researchers concluded that a high RDW count correlates with a higher mortality risk from any cause.
What is an alarming RDW count? ›How are the RDW results interpreted? A normal range for red cell distribution width is 12.2 to 16.1 percent in adult females and 11.8 to 14.5 percent in adult males. If you score outside this range, you could have a nutrient deficiency, infection, or other disorder.
What cancers are associated with low MCHC? ›What cancers are associated with low MCHC? Cancers that involve the bone marrow, like leukemia or lymphoma, are often associated with low hemoglobin. Similarly, cancers prone to causing bleeding, such as colon and stomach cancer, are associated with low MCHC.
What happens when MCV, MCH, and MCHC are low? ›A low mean corpuscular hemoglobin concentration (MCHC) means red blood cells do not have enough hemoglobin. Hemoglobin is an iron-rich protein and low MCHC blood test result may indicate anemia. Hemoglobin is responsible for the red color in blood and for circulating oxygen around the body.
What does it mean when your MCV is low? ›Low MCV means that RBC are smaller than normal and may indicate microcytic anemia. This condition may be caused by iron deficiency, lead poisoning, or thalassemia, a genetic condition that causes your body to have less hemoglobin than normal. Normal MCV may indicate normocytic anemia.
What does it mean when your MCH is low? ›Low levels of MCH can indicate iron-deficiency anemia while high levels of MCH can signal anemia caused by low levels of folic acid or vitamin B12. A healthcare provider will determine what is causing your abnormal MCH levels.
What does blood indices HCT mean? ›What Does Hematocrit Mean? Hematocrit is the percentage by volume of red cells in your blood. Blood is made up of red blood cells, white blood cells and platelets, suspended in plasma. Together, those comprise about 45% of the volume of our blood, but the specific percentages of each can vary.