Sahli+pcv practical hemoglobinometer and hematocrite

Sahli and pcv

1. Determination of Hb concentration and hematocrite value Edited by Dr. Dina hamdy merzeban Physiology Lecturer at Fayoum university

2. Determination of Hb concentration Definition:- Hb in gm/100 ml blood or % to normal, % reading of Hb is normally 100%. Clinical significance: To diagnose anemia, polycythemia. It estimates oxy & reduced Hb (not met & carboxy Hb). To determine type of anemia, calculate MCH (blood indices).

3. principal Adding HCl to the blood causes :- Hemolysis of RBCs Formation of acid hematin HCl + Hb → acid hematin (brown in color) The intensity of color is proportional to hemoglobin content in blood .

4. the role of HCl in determination of Hb content As it is hypotonic results in the hemolysis of RBCs. Convert the hemoglobin to a brownish acid hematin .

5. Apparatus Sahli apparatus (haemoglobinometer or haemometer ) which is composed of :- Sahli tube Pippette Colour comparator

6. Micro tube of sahli pipette Colour Comparator tube Sahli Tube for blood

7. steps Put 0.1 HCl till the mark 10% Add 0.02 ml blood (using the micro tube of the pipette) Shake for 15 minutes HCl + Hb → acid hematin (brown in color) Add distilled water to the acid hematin drop by drop Match colors at full arm length and against light.

8. Precautions Be sure that there is no air bubbles in the blood column. Clean the tip of pippette from any blood to avoid false high results. Withdraw the blood horizontally from the finger Ensure alcohol is completely dried Avoid compression of the finger .

9. Definition: % Ratio of RBCs volume to total blood volume. Principle : Specific gravity of RBCs :1090, WBCs & platelets 1060 plasma 1030, Haematocrite value (packed cell volume)

10. Apparatus Heparinized capillary tube (red mark)

11. Steps Pinprick the thumb Withdraw blood into the heparinized cappilary tube till ¾ th of its length Close the end of the tube with paste Place the tube in the centrifuge for 5 minutes Read the percentage of RBC to blood volume

12. What elements form the buffy colored layer on the top of packed cells? Specific gravity of WBCs = 1060 [form a thin layer (buffy coat) above RBCs]. What is normal range of PCV ? Male 46± 6% Female 42± 6%

13. Clinical significance Diagnosis of anemia, polycythemia . To determine type of anemia calculate MCV & other blood indices.

14. Describe the abnormalities of PCV? A) The conditions in which PCV is increased: Polycythemia: physiological (high altitudes or newly born) or pathological. Dehydration (vomiting, diarrhea, profuse sweating, Burns , loss of water , Hemoconcentration B) The conditions in which PCV is decreased: Anemia, female sex, overhydration & pregnancy (hemodilution)

15. Haematocrite value is higher in venous blood why? Due to Cl - shift phenomena H H2O + CO2 H2CO3 HCO3 H+ CL- Carbonic anhydrase enzyme