Abstract: Disclosed is a method for the rapid quantitative determination of low density lipoprotein (LDL) in a biological fluid sample containing LDL, very low density lipoprotein (VLDL) and high density lipoprotein (HDL). The sample is first passed through a matrix to bind LDL to the matrix. The LDL is then eluted from the matrix differentially from VLDL and HDL. A parameter representative of the concentration of a solute exiting the matrix during the interval when LDL is eluted is then determined, wherein the parameter is proportional to the amount of the LDL in the sample. The parameter may be determined, e.g., by electronically integrating under a spectrophotometrically detected peak of eluted LDL.