A novel method for estimating LDC levels: total cholesterol and non-HDLC can be used to predict the normal LDLC level in apparently healthy population

ABSTRACT BackgroundTriglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDLC), and low-density lipoprotein cholesterol (LDLC) are usually ordered together to test lipid metabolism in physical examination and clinical application. LDLC is a component of TC and its change is closely correlated to TC. ObjectiveWe aim to predict the normal LDLC level by using TG, TC, HDLC and non-HDLC (nonHDLC) in this study. MethodsTG, TC, HDLC, and LDLC data were obtained from Laboratory Information System (LIS) based on 4 years (Octo, 1, 2013-Sept, 30, 2017) period health check-up TG, TC, HDLC, and LDLC(direct clearance method) were measured using TBA2000FR biochemical analyzer. The nonHDLC was calculated with TC minus HDLC. Correlation between TG, TC, nonHDLC, and LDLC were analyzed using Spearman’s rank approach. Receiver operating characteristics curve analysis was used to evaluate the predictive of TG, TC and nonHDLC for the normal LDLC level(less than 130mg/dL). ResultsBoth TC(r = 0.870) and nonHDLC (r = 0.893) were significantly positively correlated with LDLC. Area under curve of TC and nonHDLC can be used to predict normal LDLC level. Optimal thresholds were 182.5 mg/dL(4.72 mmol/L) for TC and 135.3 mg/dL(3.50 mmol/L) for nonHDLC. Based on these optimal thresholds, less than 0.5% and 0.4% of tests with elevated LDLC might be missed, but the missing elevated LDLC is not too high(less than 147.3 mg/dL). ConclusionIf the nonHDLC is less than 135.3mg/dL(3.50 mmol/L) and/or TC is less than 182.5mg/dL(4.72 mmol/L) for the apparently healthy populations the LDLC level will be less than 130mg/dL(3.36 mmol/L). Total cholesterol and non-HDLC can be used to predict the normal LDLC level in apparently healthy population is a novel method for estimating LDC level.