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.

Effect of Adding Apolipoprotein B Testing on the Prevalence of Dyslipidemia and Risk of Cardiovascular Disease in the Korean Adult Population

“…This cutoff is recommended by the ACC/AHA guidelines for the primary prevention of CVD to define high CVD risk. This level is close to the upper limit of reference intervals from previous studies in the Korean adult population and from the Framingham Offspring Study [18,27,35]. However, a recent study conducted in the Korean population, which utilized automated analytical methods for traditional lipid tests on platforms other than Roche (e.g., Siemens), and used stored specimens for the ApoB test from the Korean Genome and Epidemiology Study cohort, found that ApoB ≥ 2.06 umol/L, as measured on the Roche platform, showed significant differences in 8-year CVD events among the study population [13].…”

“…In this study, we assessed the impact of incorporating the ApoB test into traditional lipid tests through agreement analysis and by evaluating the prevalence of dyslipidemia and high ApoB using various cutoffs in Korean adults who underwent lipid testing at local clinics and hospitals. While the ApoB test has garnered attention in Western populations, its implications and the evaluation of ApoB cutoffs have been relatively less studied in the Korean population [ 6 , 18 ]. We determined the prevalence of dyslipidemia based on both traditional lipid tests and ApoB test results.…”

“…However, ApoB levels and the prevalence of high ApoB did not significantly differ between sexes in this study. There have been inconsistent findings regarding ApoB levels by sex in the literature [ 18 , 32 , 33 ]. Serum lipid levels can be influenced by genetic background, hormonal changes, lifestyle factors, and healthcare behaviors, including access to healthcare facilities and adherence to physicians’ recommendations [ 2 , 32 , 33 ].…”

“…Traditional lipid tests, including TC, TG, HDL-C, and ApoB, were carried out using the Cholesterol Gen.2 (Roche, Mannheim, Germany), Triglyceride reagent without glycerol blank (Roche, Mannheim, Germany), HDL-Cholesterol plus 3rd generation kits, and the Tina-quant Apolipoprotein B ver.2 reagent kit (Roche, Mannheim, Germany), which is traceable to the IFCC reference material SP3-07. These tests were performed using automated Cobas 8000 system c702 analyzers (Roche, Mannheim, Germany) [ 18 , 20 ]. Non-HDL-C was calculated using the formula TC minus HDL-C. LDL-C was calculated using three equations suggested by Friedewald et al [ 21 ], Martin et al [ 22 ], and Sampson et al [ 23 ], referred to in this study as the Friedewald equation, the Martin/Hopkins equation, and the Sampson/NIH equation, respectively.…”

“…The lack of standardized analytical methods for ApoB tests has necessitated the assessment of different reference intervals across various analytical methods and populations [ 6 , 15 , 16 ]. Differences in cutoffs and reference intervals from various international guidelines for ApoB have been suggested, yet, there are no uniform cutoffs for ApoB in the Korean population [ 3 , 18 , 19 ]. Moreover, the impact of adding ApoB testing to the assessment of dyslipidemia prevalence and CVD risk in the Korean population has been less explored compared to Western populations [ 6 , 13 ].…”