The sdLDL test is used to assess cardiovascular risk by measuring the concentration of small, dense LDL particles. Elevated sdLDL levels are linked to a higher risk of developing atherosclerosis and cardiovascular conditions, even in individuals with normal LDL cholesterol levels. Symptoms of cardiovascular disease related to high sdLDL levels may include chest pain, shortness of breath, and fatigue. The test helps identify at-risk individuals and guide preventative measures or treatment strategies.