Calculated low density lipoprotein cholesterol levels frequently underestimate directly measured low density lipoprotein cholesterol determinations in patients with serum triglyceride levels < or =4.52 mmol/l: an analysis comparing the LipiDirect magnetic LDL assay with the Friedewald calculation. Export

@article{citeulike:2058968, abstract = {BACKGROUND: Increased low density lipoprotein cholesterol (LDL-C) is an established risk factor for the development of coronary artery disease (CAD). Recent guidelines detail specific LDL-C cutpoints for therapeutic goals. In practice, LDL-C is usually derived from the Friedewald formula (FF). This calculation is known to be inaccurate with serum triglyceride (TG) concentrations >4.52 mmol/l, however, its accuracy among relatively healthy patient cohorts with TG concentrations < or =4.52 mmol/l is less well studied. METHODS: We studied 661 ambulatory adults with TG concentrations < or =4.52 mmol/l and no overt CAD. Fasting venous lipid panels were obtained. LDL-C was calculated from the FF and also directly measured with the LipiDirect Magnetic LDL assay. Linear regression and paired t-test analyses were performed. RESULTS: Calculated and directly measured LDL-C concentrations were significantly different (4.26+/-0.88 vs. 4.83+/-1.06 mmol/l respectively, p<0.0001). In 93\% of measurements directly measured LDL-C exceeded calculated LDL-C. Although calculated and directly measured LDL-C concentrations were related (R=0.90), the discrepancy between them increased linearly with increasing TG concentrations (R=0.67) and clinically important differences existed at normal or slightly increased TG concentrations. Concordant results for NCEP ATP-III risk categories were present for only 48.1\% of samples. CONCLUSIONS: Significant differences between calculated and directly measured LDL-C using the LipiDirect Magnetic LDL assay exist in healthy subjects with TG < or =4.52 mmol/l. These differences are linearly related to TG concentrations and occur frequently at relatively low TG concentrations.}, address = {Department of Medicine, Division of Cardiovascular Medicine, University of Massachusetts Medical School, 55 Lake Avenue, North, Worcester, MA 01655, USA. tighed@ummhc.org}, author = {Tighe, D. A. and Ockene, I. S. and Reed, G. and Nicolosi, R.}, citeulike-article-id = {2058968}, citeulike-linkout-0 = {http://dx.doi.org/10.1016/j.cca.2005.08.026}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/16259972}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=16259972}, doi = {10.1016/j.cca.2005.08.026}, issn = {0009-8981}, journal = {Clin Chim Acta}, keywords = {ldl}, month = {March}, number = {1-2}, pages = {236--242}, posted-at = {2007-12-05 05:32:11}, priority = {4}, title = {Calculated low density lipoprotein cholesterol levels frequently underestimate directly measured low density lipoprotein cholesterol determinations in patients with serum triglyceride levels < or =4.52 mmol/l: an analysis comparing the LipiDirect magnetic LDL assay with the Friedewald calculation.}, url = {http://dx.doi.org/10.1016/j.cca.2005.08.026}, volume = {365}, year = {2006} }

TY - JOUR ID - citeulike:2058968 L3 - citeulike-article-id:2058968 N2 - BACKGROUND: Increased low density lipoprotein cholesterol (LDL-C) is an established risk factor for the development of coronary artery disease (CAD). Recent guidelines detail specific LDL-C cutpoints for therapeutic goals. In practice, LDL-C is usually derived from the Friedewald formula (FF). This calculation is known to be inaccurate with serum triglyceride (TG) concentrations >4.52 mmol/l, however, its accuracy among relatively healthy patient cohorts with TG concentrations < or =4.52 mmol/l is less well studied. METHODS: We studied 661 ambulatory adults with TG concentrations < or =4.52 mmol/l and no overt CAD. Fasting venous lipid panels were obtained. LDL-C was calculated from the FF and also directly measured with the LipiDirect Magnetic LDL assay. Linear regression and paired t-test analyses were performed. RESULTS: Calculated and directly measured LDL-C concentrations were significantly different (4.26+/-0.88 vs. 4.83+/-1.06 mmol/l respectively, p<0.0001). In 93% of measurements directly measured LDL-C exceeded calculated LDL-C. Although calculated and directly measured LDL-C concentrations were related (R=0.90), the discrepancy between them increased linearly with increasing TG concentrations (R=0.67) and clinically important differences existed at normal or slightly increased TG concentrations. Concordant results for NCEP ATP-III risk categories were present for only 48.1% of samples. CONCLUSIONS: Significant differences between calculated and directly measured LDL-C using the LipiDirect Magnetic LDL assay exist in healthy subjects with TG < or =4.52 mmol/l. These differences are linearly related to TG concentrations and occur frequently at relatively low TG concentrations. IS - 1-2 JF - Clin Chim Acta SN - 0009-8981 AD - Department of Medicine, Division of Cardiovascular Medicine, University of Massachusetts Medical School, 55 Lake Avenue, North, Worcester, MA 01655, USA. tighed@ummhc.org EP - 242 TI - Calculated low density lipoprotein cholesterol levels frequently underestimate directly measured low density lipoprotein cholesterol determinations in patients with serum triglyceride levels < or =4.52 mmol/l: an analysis comparing the LipiDirect magnetic LDL assay with the Friedewald calculation. VL - 365 SP - 236 KW - ldl AU - Tighe, DA AU - Ockene, IS AU - Reed, G AU - Nicolosi, R PY - 2006/03// UR - http://dx.doi.org/10.1016/j.cca.2005.08.026 ER -