Decreased circulating apolipoprotein concentration Decreased circulating apolipoprotein B concentration 2021-12-18T14:54:34Z The concentration of apolipoprotein B in the blood circulation is below the lower limit of normal. Apolipoprotein B is the main apolipoprotein of chylomicrons and low density lipoproteins. It occurs in plasma as two main isoforms, apoB-48 and apoB-100.