1. Other Hematological Procedures
INTRODUCTION

2. Structure of Hemoglobin
Two major components
Heme (contains iron)
Globin (the protein chain)
Hemoglobins are named in accordance with their protein chains
i.e.. Hgb A has a different protein chain than Hgb S

3. Types of Hemoglobin Hgb S Hgb C Hgbs D, E, G Hgb A Hgb A2 Hgb F
Abnormal Hgbs
Hgb S
Hgb C
Hgbs D, E, G

4. Methods of Hgb Determination
Specific gravity
Estimate of hemoglobin concentration
Drop of blood is placed in a copper sulfate solution
If drop falls rapidly the S. G. of the blood is greater than that of the copper sulfate
Blood that floats or falls slowly has low hgb concentration
Used to screen donors

5. Cyanmethemoglobin Method
Colorimetric
Based on the ability of hgb to combine with other substances and form pigments
Read spectrophotometrically
Types of hgb pigments
Oxyhemoglobin (oxygen)
Carboxyhemoglobin (carbon monoxide)
Methemoglobin
Sulfhemoglobin (irreversible)
Cyanmethemoglobin (produced chemically)

6. PRINCIPLE
Ferrous iron in hgb is oxidized to ferric state to form methemoglobin
Methemoglobin combines with cyanide to form a stable colored compound that can be read spetrophotometrically
Reagent
Drabkins reagent (potassium, sodium, and cyanide)

7. Automated Methods Hemoglobinometers (Hemocue) Principle RBCs lysed
Hgb released and combined with cyanide
Measured absorbance of pigment is proportional to hgb
Interfering substances
Lipemia, high WBC count and RBC abnormalities that prevent lysing of cells

9. Normal Values Infants (at birth): 16.0-23.0 g/dl
Childhood (3 months-13 years): g/dl
Adult males: g/dl
Adult females: g/dl

10. Hematocrit Definition- the volume of RBCs in a given volume of blood
Clinical significance
Estimate of RBC volume
Used with hgb value to assess patient’s oxygen-carrying capability

11. Manual Hematocrit Capillary tube (anticoagulated whole blood)
centrifuged for 5 minute at 10,000 rpm
RBCs and other cells -bottom
Plasma-top
Percentage is determined
special reader is used
RBC volume in relation to the total volume of whole blood

12. Automated Hematocrit Blood is passed through an orifice
Individual RBCs pass through an electrical current and cause an impedance change
Degree of change is affected by sized of cell
Hct is calculated by summing the electronic volume of the RBCs in the patient sample
Interfering substance
High WBC count, very large platelets, very small RBCs (microcytic)

13. Normal Values Infants (at birth): 51-61% Childhood: 34-42%
Adult male: %
Adult female: %
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