Reference interval for the apolipoprotein B-48 concentration in healthy Japanese individuals

Aim: small intestine-derived chylomicrons and chylomicron remnants,which are predominant in patients with postprandial hypertriglyceridemia,chylomicron syndrome and/or familial dyslipidemia,carry one molecule of apolipoprotein b-48 (apo b-48) per lipoprotein particle. we investigated the reference interval for the apo b-48 concentration. methods: we studied 516 individuals who provided written informed consent and confirmed that they were not taking any medications. bmi,waist circumference,blood pressure and the fasting serum concentrations of ldl-c,triglyceride (tg),hdl-c and apo b-48 were measured. the apo b-48 concentrations were compared according to sex,a pre- or postmenopausal status,dyslipidemia (ldl-c ≥140 mg/ dl,tg ≥150 mg/dl,hdl-c <40 mg/dl),metabolic syndrome (mets) and the number of risk factors. results: the fasting apo b-48 concentrations (mean±sd) were significantly higher in men than in women (3.8±3.3 μg/ml vs 2.4±1.9 μg/ml,p<0.001),subjects with a bmi of ≥25 kg/m2 versus a bmi of <25 kg/m2 (4.4±3.7 μg/ml vs 2.8±2.4 μg/ml,p<0.001) and those with versus without mets (6.5±4.3 μg/ml vs 3.0±2.6 μg/ml,p<0.001). high apo b-48 concentrations were also observed in correlation with the number of risk factors for the mets. the upper reference limit of apo b-48 was estimated to be 5.7 μg/ml among the 332 patients with normolipidemia,excluding those exhibiting a mean value above ±2.58 standard deviations (sds),as the mean and range of mean ±1.96 sd were calculated to be 2.04 μg/ml (reference value) and 0.74 to 5.65 μg/ml (reference interval),respectively. conclusions: based on our study of normolipidemic patients,the upper reference limit for the fasting apo b-48 concentration is estimated to be 5.7 μg/ml.