Apolipoprotein A-I (apo A-I) may be ordered, along with other lipid tests, as part of a profile to help determine a person's risk of developing cardiovascular disease (CVD). It may be used as an alternative to a high-density lipoprotein (HDL) test. Levels of apo A-I tend to rise and fall with HDL levels, and deficiencies in apo A-I correlate with an increased risk of developing CVD. An apo A-I may be ordered along with an apolipoprotein B (apo B) test to determine an apo B/apo A-I ratio. This ratio is sometimes used as an alternative to a total cholesterol/HDL ratio (sometimes reported as part of a lipid profile) to evaluate risk for developing CVD. Apo A-I may be measured when someone has a personal or family history of abnormal lipid levels and/or premature CVD.