Exploring Utilization and Establishing Reference Intervals for the Apolipoprotein B Test in the Korean Population

Abstract

We investigated the reference intervals for Apolipoprotein B (ApoB), a valuable biomarker for cardiovascular diseases, in Korean adults who had undergone health check-ups and showed normal lipid levels under traditional lipid tests, including total cholesterol, triglyceride, and high-density lipoprotein cholesterol, along with ApoB. We compared the findings with different cutoffs for ApoB from international clinical guidelines. Among a total of 264,105 traditional lipid test sets, only 464 (0.2%) included ApoB tests, indicating underutilization of this test in health check-up clinics in Korea. From these 464 samples, 334 ApoB results (164 men and 170 women) with normal traditional lipid test results were used to establish reference intervals. Using the parametric method (mean ± 2 SD), the reference intervals ranged from 46 to 134 mg/dL for men and 49 to 129 mg/dL for women. Employing the non-parametric method (central 95th percentile value), the reference intervals ranged from 50 to 131 mg/dL for men and 51 to 127 mg/dL for women. The prevalence of high ApoB did not significantly differ by sex when considering the established reference intervals for each sex and the cutoffs recommended by international clinical guidelines. This study enhances knowledge on ApoB reference intervals in the Korean population, and it will in aid test result interpretation for clinicians and laboratories.

Keywords: ApoB; Korean; apolipoprotein B; dyslipidemia; lipid; reference interval.

Figure 1

Study scheme.

Figure 2

Reference intervals and ranges of apolipoprotein B (ApoB) levels investigated in Korean populations using different statistical approaches, analytical methods, and cutoff values provided by international guidelines for dyslipidemia. The upper limits of the reference intervals obtained from this study’s population are represented by the numbers in red while the cutoff values provided by the international guidelines are shown in blue. The x-axis indicates the sources of the reference intervals and ApoB ranges while the y-axis represents the ApoB levels in mg/dL. Previous studies on ApoB in the Korean population, including those by Kim et al. (2017) [29], Jang et al. (2017) [27], Cho et al. (2012) [26], Kim et al. (2017) [28], Ryoo et al. (2011) [21], Ryoo et al. (2013) [20], and Bae et al. [25], employed various analytical methods. Data were presented in descending order of the upper limits.

Figure 3

Apolipoprotein B levels observed in the 334 Korean adults for the establishment of the reference intervals and the 130 Korean adults excluded from the reference interval establishment. The yellow horizontal lines represent the highest and lowest upper limits of the established reference intervals in this study’s population. The upper yellow horizontal line represents 134 mg/dL for the men, which was determined from the mean (±2 SD) value, while the lower yellow horizontal line represents 127 mg/dL for the women, which was derived from the central 95th percentile value.

Figure 4

Prevalence of high apolipoprotein B (ApoB) levels using different cutoff values (upper limits of the reference intervals) in (a) the 334 Korean adults who underwent health check-ups and had traditional lipid test results within the NCEP ATP III criteria and (b) the 130 Korean adults who were excluded from the population for reference interval establishment due to their traditional lipid result criteria. The x-axis represents the sources and cutoff values for the ApoB levels. The y-axis on the left represents the number of subjects, and the y-axis on the right represents the percentages (%) of study subjects with high ApoB levels. “M” represents men and “F” represents women.