Here are the guidelines based on the government’s National Cholesterol Education Program

Total Cholesterol

Desirable Less than 200 mg/dl (5.2 mmol/L)*
Borderline-high 200-239 gm/dl (5.2-6.2 mmol/L)
High 240 mg/dl (6.2 mmol/L0 or more

LDL Cholesterol

Desirable Less than 130 mg/dl (3.4 mmol/L)*
Borderline-high 130-159 gm/dl (3.4-4.1 mmol/L)
High 160 mg/dl or more (4.1 mmol/L)

HDL Cholesterol+

Low       Less than 35 mg/dl (0.9 mmol/L)*
High 60 mg/dl (1.6 mmol/L) 0 or more

*Milligrams (mg) are used in the U.S., millimoles (mmol) in Canada and other countries.

+Editor's note:  LDL levels are misleading because they are mathematically derived from you HDL numbers.  As a result they are not true numbers.  In some cases they cause a misdiagnosis of concern or non concern.

In Canada, England, and many other countries, blood cholesterol is measured in millimoles per liter of blood (a millimole, one-thousandth of a mole, is a chemical measure based on the molecular weight of a substance), abbreviated as mmol/L. This is called the International System. In the U.S., blood cholesterol is usually measured in milligrams per deciliter (one-tenth of a liter) of blood, or mg/dl—though the International System is also increasingly being used here.

To convert a result from the International System to the American system, multiply it by 38.67. Thus your figure, 6.5, equals 251, which is high. For a quick, a rough estimate, simply multiply by 40.

To convert an American number to the International System, divide by 38.67. For a rough estimate, divide the milligrams by 40 to get the millimoles.

The same formulas are used to convert total, HDL, and LDL cholesterol.