Lp(a) 21 FS is a particle-enhanced immunoturbidimetric test to determine lipoprotein (a) [Lp(a)] in serum and plasma. Lp(a) is a particle consisting of a LDL (LDL: low density lipoprotein) molecule bound to apolipoprotein (a) which varies in size depending on the isoforms. Lp(a) is considered an atherogenic risk factor which is independent of other lipid parameters. Increased levels have a high predictive value for coronary heart disease.