Blood Count Test (CBC)

 


1. Objective:
The objective of this test was to determine the total number of red blood cells (RBCs), white blood cells (WBCs), and platelets, along with hemoglobin concentration, hematocrit, and other related indices in a blood sample.

2. Principle:
The test was based on the automated or manual counting of blood cells using electrical impedance or microscopic methods. In the automated method, blood cells passed through an electric field and caused changes in resistance that were counted electronically. In manual methods, cells were visually counted using a hemocytometer.

3. Materials:

  • EDTA anticoagulated whole blood sample
  • Microscope slides and cover slips
  • Hemocytometer (Neubauer chamber)

  • RBC and WBC diluting fluids
  • Hemoglobinometer (or automated analyzer)
  • Pipettes
  • Microscope

  • Gloves and sterile lancet (for sample collection)

 

4. Procedure (Microscopic/Manual):

  1. The patient’s blood sample was collected in an EDTA tube and mixed gently.
  2. For RBC and WBC counts, the blood was diluted with the appropriate diluting fluid.

  1. The diluted sample was loaded into the hemocytometer.
  2. The cells were allowed to settle, and the chamber was examined under the microscope.
  3. RBCs and WBCs were counted in the designated squares of the Neubauer grid.

  1. The hemoglobin concentration was determined using Sahli’s or cyanmethemoglobin method (if manual).
  2. The results were calculated and recorded.

5. Result:
Normal reference ranges:

  • RBC count: 4.5–6.0 million/µL (males), 4.0–5.5 million/µL (females)
  • WBC count: 4,000–11,000/µL

  • Platelet count: 150,000–450,000/µL
  • Hemoglobin: 13–17 g/dL (males), 12–15 g/dL (females)

  • Hematocrit: 40–50% (males), 36–44% (females)

6. Uses:

  • To evaluate general health and detect a variety of disorders such as anemia, infection, and leukemia.

  • To monitor medical conditions and effectiveness of treatments.
  • To assess blood loss or bone marrow function.

7. Consultation:
Abnormal results indicated possible conditions like anemia, infection, or thrombocytopenia. The patient was advised to consult a physician for further evaluation, additional tests, and treatment depending on which blood component was affected.

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