Hemoglobin & Hematocrit Value Calculation (PDF)

Estimation of hemoglobin content (Sahli Apparatus/Haemometer) & Hematocrit value (HV, PCV) & Blood indices & CBC interpretation Presented by: Dr: Asmaa Tarek Lecturer of physiology Lateral standard tubes containing standard amount of acid hematin from blood of 15 g % H...

Estimation of hemoglobin content (Sahli Apparatus/Haemometer) & Hematocrit value (HV, PCV) & Blood indices & CBC interpretation Presented by: Dr: Asmaa Tarek Lecturer of physiology Lateral standard tubes containing standard amount of acid hematin from blood of 15 g % Hb and their color is stable. Haemometer Tube g% % 22 140 2 10 Blood pipette 20 µl = 20 mm3 = 0.02 ml  Distilled water Blood Dropper HCL  Principle Conversion of hemoglobin to acid hematin and comparing visually the colour developed with that standard glass (colouremetric method).  Procedure 1-Fill the haemometer tube with diluted HCl till the level 10% graduation of the tube. 2- Suck blood into the capillary tube until 20 cmm mark is reached. 3- Blow blood out of the capillary pipette into HCl haemometer. 4- Mix the blood with the acid solution by a glass rod by rotating and gently moving up and down. 5- Put the haemometer tube in the comparator and leave for 5 minutes. 6- Take the Hb tube out of the comparator and distilled water drop by drop stirring the mixture each time and comparing the color with the standard. 7- Hold the comparator at eye level away from your face against bright but diffused light. 8- Read against both scales, the Hb level using the g% scale and the % as normal using the % scale. Read at the lower border of the fluid concave surface  Results Normal Abnormal (15g%) Male Female Decrease Increase (14-16 g%) (12-15 g%) (< 11g%) Anemia Polycythemia  Advantage: This method is simple, does not require any costly apparatus, and can be used in mass surveys.  Disadvantages: Subjective visual colour comparison. Need accurate pipetting. Estimation of only acid hematin formed. Hematocrit Value  Hematocrit value (Packed Cell volume) Definition: Blood is composed of plasma and cells ( RBCs , WBCs & Platelets ) since RBCs are the most abundant cells so; Haematocrit value is defined as the volume occupied by RBCs relative to whole blood so, it’s the volume percentage of RBCs in blood Normal values: Male : 45 % Female: 42 % Children: 40 % HV = Volume of RBCs X 100 volume of (RBCs+WBCs+platelets+Plasma) So HV = volume of RBCs X 100 total volume of blood  Measurement HV is measured by centrifugation of heparinized blood in a capillary tube ( micro haematocrit tube) Steps : 1. Clean the end of your middle finger with alcohol swab and let the finger to dry in air. 2. Remove a sterile disposable blood lancet from its package without touching the sharp end. 3. Puncture the skin on the side near the tip of middle finger with the lancet. 4. Touch a drop of blood with the end of heparinized microhaematocrit capillary tube 5. Hold the tube tilted slightly upwards so blood will move into the tube by capillarity. 6. Seal one end of the tube by clay at 90 °. 7.Place the filled and sealed capillary tubes into the centrifuge. The sealed ends should point toward the outside of the centrifuge. The duplicate samples should be placed opposite each other in order to balance the centrifuge. 8. After the centrifuge has stopped, remove the specimen tube. The red blood cells have been packed into the bottom of the tube. The clear liquid on top of the cells is the plasma.  How to measure Place the haematocrit tube on the chart such that: the lower end of the tube along the zero line of the scale such that the clay (plasticin) is below the zero line. Move the tube along those lines until the top of the plasma intersects the top line of the scale. N.B :If the tube is very full, you may need to use the scale on the right side. Then read the line where the RBCs meet the plasma Micro haematocrit capillary tube reader Interpretation of haematocrit value Hematocrit value is increased in : 1.Polycythemia 2. Dehydration : as in gastroenteritis, as the plasma volume is reduced so the hematocrit value is increased. Haematocrit value is decreased in: 1. Anemia : due to decreased number of RBCs, but its not used to determine type of anemia. 2. Overhydration: leading to increase plasma volume and so haematocrit value drops. Haematocrit value may also be measured using Wintrobe tube, which is a bigger graduated tube the HV can be directly read after centrifugation. Normal Anemia Polycythemia  BLOOD INDICES They are calculations that provide information about haemoglobin content and size of RBCs which aid in diagnosis and classification of anemia. They include: 1. Mean corpuscular volume (MCV) 2. Mean corpuscular haemoglobin (MCH) 3. Mean corpuscular haemoglobin concentration (MCHC) Mean corpuscular volume (MCV) It is the average size of a RBC. It is calculated by dividing HV by RBCs count. MCV = H.V × 10 RBCs count in millions /µL Normally : 80 - 95 fL (μm³) Microcyte ˂ 80 fL e.g. iron deficiency anemia. Macrocyte ˃ 95 fL e.g. vitamin B12 deficiency anemia. NB. Femtoliter = 10¯¹⁵ liter Mean corpuscular hemoglobin (MCH) It is the average amount of haemoglobin per RBC. It is calculated by dividing the haemoglobin by RBCs count MCH = Hb content (g/dL) × 10 RBCs count in millions/µL Normally : 27: 33 pg NB. Picogram = 10⁻¹² g Mean corpuscular haemoglobin concentration (MCHC) It is the average Hb concentration in a single RBC. It Is calculated by dividing the haemoglobin by the hematocrit. MCHC = Hb content (g/dL) × 100 hematocrit Normally : 33 % → Normochromic ˃ 35 % → Hyperchromic anemia e.g. hereditary spherocytosis. ˂ 33 % → Hypochromic anemia e.g. iron deficiency anemia. MCHC is not changed in vitamin B12 deficiency.  BLOOD INDICES MCV = H.V X 10 RBCs count in millions /µL MCH = Hb RBCs count in millions /µL X 10 MCHC = Hb X 100 H.V Thank you