A simple and rapid analytical assay for determination of total cholesterol, HDL-cholesterol and triglycerides in capillary blood samples has been compared with established laboratory methods in a group of 41 test subjects. The new method produces results that are fully acceptable for determination of these three lipid parameters, and agree well with the results obtained in serum by established laboratory methods. The Cholestech LDX analyser may be useful for providing rapid and accurate measurements of the lipid profile, including total cholesterol, triglycerides and HDL-cholesterol. Its small size, the speed of analysis and the fact that it is easy to use make the Cholestech LDX a suitable instrument for use in out-patient clinics and primary care medicine.