Falsely Low LDL Cholesterol Results and Cholestasis

Abstract

LDL cholesterol (LDL-C) is commonly measured for evaluation and management of hypercholesterolemia. The Friedewald formula [LDL-C = (total cholesterol)—(HDL cholesterol)—triglycerides/2.2 for mmol/L] is commonly used to determine LDL-C, but this method has some well-established shortcomings and may not meet the National Cholesterol Education Program criteria of total error <12% (1)(2)(3). Another approach is the use of homogeneous methods for direct quantification of LDL-C. In our laboratory, we use the Kyowa Medex® method 2nd-generation assay on a Roche Cobas Integra 800® analyzer (1)(3)(4). We report a case of falsely low LDL-C results in a man 69 years of age with type IIa dyslipidemia according to the Frederickson classification. The patient was admitted to the hospital for coronary heart disease and weight loss of 8 kg over a 3-week period. On admission, we performed a lipid evaluation on the Cobas Integra 800. The results revealed a discrepancy between the total cholesterol (TC; 9.18 mmol/L), and the sum of direct LDL-C (3.55 mmol/L) …