To determine risk of developing heart disease. Screening: as part of a regular health exam with a lipid panel when no risk factors for heart disease are present; once every 4 to 6 yrs in adults; youth should have a lipid panel once between ages of 9 and 11 and between age of 17 and 21. Monitoring: may be done frequently and at regular intervals when risk factors for heart disease are present, when prior results showed high risk levels, and/or when undergoing treatment for unhealthy lipid levels