Performance of calculated and directly measured low-density lipoprotein cholesterol in a pediatric population

Stephen M. Roper, Jing Cao, Estella Tam, Sridevi Devaraj

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

Objectives: An assessment of methods for the accurate measurement of low-density lipoprotein cholesterol (LDLC) at decreased concentrations has not yet been carried out. We evaluated the performance of the Friedewald equation, a direct enzymatic assay, and a novel equation for determining LDL-C levels in a pediatric population with elevated triglycerides and reduced LDL-C levels. Methods: LDL-C concentrations of 127 pediatric patients were determined by the Friedewald equation, a direct enzymatic assay, and a novel equation. The bias of each approach was assessed at selected LDL-C cutoffs and after stratifying samples by triglyceride content. The concordance of each approach, relative to the reference method, was determined at LDL-C cut-points of less than 70, 70 to 99, and 100 to 129 mg/dL. Results: The Friedewald equation substantially underestimated pediatric LDL-C concentrations below 100 mg/dL in the presence of elevated triglycerides. The Ortho Clinical Diagnostics (Raritan, NJ) direct LDL assay was positively biased at low LDL-C levels. The novel equation most effectively reduced the bias of the Friedewald equation at all LDL-C concentrations and increased the concordance of sample classification to the reference method. Conclusions: The novel equation should be used for accurate measurement of pediatric LDL-C when the concentration is below 100 mg/dL in the presence of elevated triglycerides (150-399 mg/dL). .

Original languageEnglish (US)
Pages (from-to)42-48
Number of pages7
JournalAmerican journal of clinical pathology
Volume148
Issue number1
DOIs
StatePublished - 2017
Externally publishedYes

Keywords

  • Calculated LDL-C
  • Direct-measured LDL-C
  • Friedewald equation
  • Low-density lipoprotein cholesterol

ASJC Scopus subject areas

  • Pathology and Forensic Medicine

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