What is the formula for calculating Total cholesterol?

Total cholesterol is calculated using the formula that incorporates the levels of high-density lipoprotein (HDL), low-density lipoprotein (LDL), and triglycerides (TG). The correct choice indicates that total cholesterol is obtained by adding the HDL and LDL cholesterol values together and incorporating triglycerides into the calculation. Specifically, triglycerides are divided by 5 because this provides an estimation of the very-low-density lipoprotein (VLDL) cholesterol associated with the triglycerides. This method is rooted in the Friedewald equation, which simplifies the estimation of lipid levels.

The formula recognizes that HDL cholesterol is considered protective against heart disease, while LDL is often termed "bad" cholesterol due to its association with increased risk of cardiovascular issues. Therefore, combining these values with an appropriate adjustment for triglycerides allows healthcare providers to estimate total cholesterol accurately and holistically reflect an individual's cholesterol status.

In this context, other options do not correctly calculate total cholesterol, either by not including all necessary components or by incorrectly adjusting the triglyceride value.