The Correlation Between Direct and Calculated LDL-C Among Patients Referred for Lipid Profile at a Tertiary Care Hospital--Sri Lanka
The validity of Friedewald formula (FF) in the presence of >400 mg/dL of triglyceride is considered low. However, patients with metabolic syndrome have altered lipoprotein metabolism that would affect the usual ratios between different lipid fractions; especially triglycerides. Despite these pitf...
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Veröffentlicht in: | Indian journal of clinical biochemistry 2022-05, Vol.34 (S1), p.S184 |
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Sprache: | eng |
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Zusammenfassung: | The validity of Friedewald formula (FF) in the presence of >400 mg/dL of triglyceride is considered low. However, patients with metabolic syndrome have altered lipoprotein metabolism that would affect the usual ratios between different lipid fractions; especially triglycerides. Despite these pitfalls FF is widely used in the clinical laboratory to cater all patients in general regardless of their disease conditions. The aim of this study was to describe the correlation between direct and calculated LDL-c among patients regardless of their diagnoses as referred to a laboratory. A cross sectional comparison study was conducted among 291 patients referred for lipid profile to the laboratory at a tertiary care hospital - Sri Lanka during a period of 1 month. Direct LDL-c and conventional lipid profile with calculated LDL-c by FF were measured. The mean fasting triglyceride level among the general patient population catered by the laboratory was 138.6 mg/dL (SD:64.9) with a range from 45-464 mg/dL. The mean calculated LDL-c was 103.6 mg/dL (SD:38.4, range: 14.3-233 mg/dL) while mean direct LDL-c measurement was 252.2 mg/dL (SD:39.6, range: 11.2-252.2 mg/dL). The calculated and the direct LDL-c measurements had good correlation at different levels of triglycerides ([r.sup.2]=0.9319 at Triglyceride 200 mg/dL). The use of calculated LDL-c caused a mean negative bias of 7.38 mg/dL and according to the Bland-Altman plot lower concentrations were more affected. The percentage bias when using calculated LDL-c was >5.46% (the desirable specification for bias) in 63.9% of the patients while only 1/3 of them had a triglyceride level >150 mg/dL and the majority (117; 63%) had normal triglyceride levels. Calculated LDL-c by FF may result in clinically significant bias even in patients with normal triglyceride levels. Therefore, normal triglyceride levels do not warrant accurate LDL-c results by FF especially if the metabolic disease status of the patient is unknown. |
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ISSN: | 0970-1915 |