Results

1. Generate a calibration curve. Knowing that 0% hemolysis happened in Tube #1 (0.9% NaCl = isotonic solution) and that 100% hemolysis happened in Tube #6 (0.0% NaCl = hypertonic solution), plot a linear relationship between % of hemolysis vs. OD.
   
   


2. Determine the % of hemolysis for each of your remaining tubes from your calibration curve. This is done by interpolating the % of hemolysis of your tubes with their respective ODs. Simply draw a vertical line from the x-axis at a the OD value from each tube until it crosses the linear relationship line, and then draw a horizontal line to the y-axis. The y-value at this point is equal to the % of hemolysis of your sample.

Example: from the calibration curve above, a tube with an OD reading of 0.35, will have a % of hemolysis of 80%

3. Calculate the Osmolarity of each solution to later plot the % of hemolysis vs. osmolarity. Osmolarity is calulated in 2 steps:
   
   Ex. for 0.3% NaCl
   Molarity of NaCl = (0.3/100ml) / (molecular weight of NaCl)
   Osmolarity = 2 * Molarity of NaCl
   2 because Na+ and Cl- are the two impermeable molecules in solution
   
   

  Questions to think about:

• What would be the significance of a shift to the right- or to the left- of the osmotic fragility curve?
• How would the shape of the erythrocyte (sickle cells vs. normal erythrocytes), its surface area to volume ratio (biconcave shape vs. spherocyte) shift the osmotic fragility curve?