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Total count


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Total count

  1. 1. TOTAL LEUKOCYTE COUNT Dr.Gopala Krishnan.B.Yadav
  2. 2.  It is a blood test to measure the number of white blood cells
  3. 3.  It is a blood test to measure the number of white blood cells Normal range category Range / microlitre adults 4000-10,000 birth 10,000-25,000 1-3yr 6000-18,000 4-7yr 6000-15,000 8-12yr 45000-13,500
  4. 4.  Alteration in number and type of leukocytes is often associated with disease process & hence the count is informative
  5. 5. LEUCOCYTOSIS Infections Malignancy like leukemia Severe emotional or physical stress Pregnancy
  6. 6. LEUCOPENIA Infections bacterial-(typhoid,paratyphoid) viral(hepatitis) protozoa(malaria) Some cases of leukemia Primary bone marrow depression (Aplastic anaemia) Secondary bone marrow depression (drugs,radiation) anaemia ( megaloblastic)
  7. 7. LETS COUNT…
  8. 8. SPECIMENS Double oxalated or EDTA blood Capillary blood
  9. 9. REQUIREMENTS Microscope Hemocytometer Wbc diluting fluid
  10. 10. HEMOCYTOMETER Hemo: blood Cyto: cell Meter: measurement/counter Thus, it is an instrument used to count the blood cells.
  11. 11. It includes:a) Neubauer’s slideb) Cover slipc) RBC pipetted) WBC pipette
  12. 12. NEUBAUER’S SLIDE It is the name given to a thick glass slide . In the centre of the slide, there is an H- shaped groove. On the two sides of the central horizontal bar, there are scales for counting the blood cells The depth of the scales is 1/10mm or 0.1mm.
  13. 13. NEUBAUER’S CHAMBER Neubauer’s slide with a cover slip over it, is called a Neubauer’s chamber Four corner squares are meant for WBC counting. Total = 64 small squares
  14. 14. WBC PIPETTE It has a white bead It has graduations upto mark 11 Size of bulb is smaller Size of lumen is larger
  15. 15. WBC DILUTING FLUID:It is prepared as follows: a) Glacial acetic acid: 2.0 ml b) 1 % (w/v) gentian violet: 1.0 ml c) Distilled water: 97 ml
  16. 16. PRINCIPLE The glacial acetic acid lyses the red cells while the gentian violet slightly stains the nuclei of the leukocytes. The blood specimen is diluted 1:20 in a WBC pipette with the diluting fluid. The cells are counted under low power of the micro scope by using a counting chamber. The number of cells in undiluted blood are reported per cu mm (µl) of whole blood
  17. 17. PROCEDURE Draw blood up to 0.5 mark of a WBC pipette. Carefully, wipe excess blood outside the pipette by using cotton. Draw diluting fluid up to 11 mark. Mix the contents in the pipette and after five minutes by discarding few drops, fill the counting chamber and allow the cells to settle for two to three minutes.
  18. 18. FOCUSING 4X to see the general formation of slide. 10X for WBC counting
  19. 19. COUNTING RULE Do not count cells touching  Bottom line  Right line  This is to avoid double counting.
  20. 20. WBC COUNTING
  21. 21. DILUTION FACTOR0.5 part of blood is mixed in 10 parts of fluidSo, 1 part of blood is in 20 parts of fluidThus, dilution factor for WBC counting is 20.
  22. 22. CALCULATION OF THE VOLUME OF WBC SQUARES Length of one small square = 1/4mm Width of one small square = 1/4mm Depth of one small square = 1/10mm Volume of one small square = 1/4 x 1/4 x 1/10 = 1/160mm³
  23. 23. WBC COUNTING Total no. of WBCs in 64 smallest squares = X No. of WBCs in one smallest square = X/64 Volume of one smallest square = 1/160mm³ No. of WBCs in 1/160mm³ = X/64 No. of WBCs in 1mm³ = X/64 x 160 No. of WBCs in 20 times diluted blood = X/64 x 160 No. of WBCs in undiluted blood = X/64 x 160 x 20/mm³ = X x 50/mm³