After discarding the first 3 drops, charge the counting chamber of the hemacytometer by gently squeezing the reservoir.
8. Using the high power objective, count the red blood cells in the red blood cell counting areas.
9. Calculations: Multiply the number of cells counted by 10,000 to obtain the red cell count.
Example: The number of cell in the 5 counting squares was 423.
The cell count = 423 x 10,000
Of the many methods of hemoglobin estimation, the most accurate is reading of hemoglobin as oxyhemoglobin in the photometer, after dilution of the blood with a weak alkali. The HadenHausse, Sahli-Hellige, and Newcomer tests, based on acid hematin formed by the action of hydrochloric acid on hemoglobin, are sufficiently accurate for routine examination, provided they are properly done. Since relatively few ships and stations are equipped with a photometer, we will discuss the Sahli-Hellige method.
Materials Required for Sahli-Hellige Test
1. With a medicine dropper, place 5 drops of the 0.lN HCl in the bottom of the graduated tube. Place the tube in the color comparator.
2. Using well-mixed venous blood or fingertip blood, fill the pipette to the 20 mm3 mark.
3. Wipe blood from the outside of the pipette. Transfer blood to the Sahli tube. Note the time.
4. Aspirate distilled water into the pipette two or three times and transfer these washings to the tube.
5. Shake until the blood is well mixed and the tube is a uniform color.
6. Add distilled water, drop by drop, each time mixing the solution with the stirring rod. Keep adding water and mixing until the color of the solution matches the standards on either side. Remove the stirring rod from the tube each time before comparing. Natural light makes more accurate readings possible.
7. Five minutes after time noted, read the result from the scale on the tube by noting the graduation mark at the lower edge of the meniscus. Read and report both scales. Reporting. Findings are reported both in grams per 100 ml of whole blood and in percentsides. On one side is the percentage ages of normal values. There are a number of