LDL calculation Formula:
   LDL = TC - HDL - TG/5.0
Where:
   LDL: Low Density Lipoprotein Cholesterol
   TC: Total Cholesterol
   HDL: High Density Lipoprotein Cholesterol
   TG: Triglycerides

Reference:
W., Friedewald, R., Levy and D., Fredrickson. Estimation of the Concentration of Low-Density Lipoprotein Cholesterol in Plasma, Without Use of the Preparative Ultracentrifuge. Clinical Chemistry. 1972. 18:499-502