Acts of medical biology "dosage of apolipoprotein A1" and "determination of apolipoprotein B" are to determine the concentration of these biological factors by immunoturbidimetry (most tests) or immunonephelemetry. They can be made through the exploration of a lipid abnormality (EAL), in addition to assays of total cholesterol, triglycerides, HDL-cholesterol (HDL-C) and calculating the concentration of LDL cholesterol (LDL-C) according to the Friedewald formula.