Core Lab for Clinical Studies (CLCS) is a clinical lab that supports research in all departments at Washington University as well as at external sites. It was founded in 1972 as a support lab for the NIH-funded Coronary Primary Prevention Trial, an early multicenter study designed to determine whether cholesterol lowering therapy reduced coronary heart disease. The participating clinical sites worked together to develop analytical methods for the then new biomarkers known as low density lipoprotein (LDL) and high density lipoprotein (HDL). Interest in cholesterol metabolism has been maintained and CLCS is a founding and current member of the Lipid Standardization Program of the Centers for Disease Control, a group tasked with evaluating cholesterol and related testing across instruments and methods. CLCS currently performs the standard clinical lipid panel, apolipoprotein A1 and apolipoprotein B, and, as of 2023, lipoprotein(a).

Over time CLCS extended its services, becoming a general CLIA-certified laboratory and it now acts as a central lab for a variety of local and multicenter clinical trials. It supports outpatient offices in the Center for Advanced Medicine at Washington University and also research done in the Washington University Diabetes Research Center (DRC), Nutrition Obesity Research Center (NORC) and the Washington University Institute for Clinical and Translational Sciences (ICTS). CLCS is actively engaged in laboratory research and testing with partners in industry and academia.

CLCS is located in the Division of Endocrinology, Metabolism and Lipid Research in the Department of Medicine at Washington University School of Medicine.