Separation of Components Plasma = Less Dense Hematocrit “Packed Cells” More Dense Platelets / WBC’s

Hematocrite value (H.V.) or packed cell volume (PCV) Definition:- H.V. is the volume of RBCs in 100 ml blood or it is the percentage of the volume of RBCs to the volume of whole blood. Volume of RBCs = × 100 Volume of blood Materials:- Microhematocrite tube (75 mm long, 1 mm pore, heparinized ) Microhematocrite centrifuge. Microhematocrite tube reader. Sterile lancet, 70 % ethyl alcohol.

Procedure:- Obtain blood drop by pricking the thumb. Micro hematocrite tube is filled up to it's 2/3 with blood sample by touch the drop of blood by one end of the tube. Close the empty end of the tube by plasticine. Centrifuge the tube at per minute for 5 minutes. Remove the tube and read H.V. by putting the tube on special micro hematocrite scale. Normal value:- adult male. 45%- 47 % adult female. 42 % -44% Higher in new born %

Hematocrite (PCV) determination Capillary methods

Female:36-48% Male:45-47%

Hematocrite (PCV) determination Wontrob methods

Significance of the hematocrite The PCV layer normally 45-47% Increased in polycthemia and dehydration Decreased in anemia The Buffy coat normally 1% Increased in leukocytosis and leukemia Plasma layer Colour : Normally faint yellow Deep yellow color indicate Jaundice Red color indicate Hemolysis

Determination of Hb values Haemoglobin can be measured manual or automatic. Two method are commonly used: 1.Oxyhaemoglobin (Hbo 2 method). 2.Haemiglobincyanid. (HicN;Cyanmethaemoglobin ) A major a advantage of the HicN method is availability of stable and reliable reference preparation. Other methods: Sahli’s acid haematin and alkalin- haematin method.

Cyanmethaemoglobin method Use Drabkins solution which contain potassium cyanide and potassium ferricynide at PH Hb oxidation to methaemoglbin by potassium ferricynide then combine to potassium cyanide to form cyanmethaemoglobin which measure at 540 nm by spectrophotometer.

Normal rage of Hb in g/dl Hb g/dl= Men g/dl Women g/dl At birth g/dl Principle of Hb cyanide method Blood is diluted in a solution: contains potassium cyanide + potassium ferricyanide (Drabkin solution) As a result this reaction will occure: Hgb  methemoglobin  HiCN (cyanmethemoglobin)

Methods Prepare the working solution of diluted drabkin (one volume drabkin+ four volumes distilled water) Set spectrophotometer to 0.0 reading at 540 wave length, using blank (diluted drabkin solution) 10µL of blood in 2.5 mL of working solution in the cuvet, Cover and invert the tube several times. Let it stand at R.T for 5-10 minutes to insure complete conversion Put the cuvet in the spectrophotometer. Continue reading patient samples and determine Hb value of the sample by multiplying the absorbance by the factor (36.77).