APOB and chronic kidney disease: However, APOB - the quantitative marker of IDL and LDL particles in serum, did not decrease, thus we might conclude that the ε2 carriers in the G4 CKD stage had lower APOE level in IDL + LDL particles, in comparison to the G3a CKD stage patients, but the amount of these lipoproteins was constant along with the CKD progression.