Creating an Influence on Cardiovascular Disease Management

In the realm of cardiovascular health, low-density lipoprotein cholesterol (LDL-C) takes centre stage as the key target for diagnosis and treatment of cardiovascular disease (CVD). While beta-quantitation (BQ) remains as the gold standard for direct measurement of LDL-C, clinical laboratories continue to lean on the simplicity of the conventional Friedewald equation to report calculated LDL-C results to patients. Given the critical role LDL-C plays in CVD risk assessment, the Chemical Metrology Laboratory (CML) of Health Sciences Authority (HSA), Singapore delved into the accuracy of the Friedewald equation and alternative equations, particularly the Martin/Hopkins and Sampson equations.

HSA CML leveraged data from clinical laboratories participating in its regular External Quality Assessment (EQA) programmes across 5 years. The calculated LDL-C values were compared against reference values determined by CML’s beta-quantitation-isotope dilution mass spectrometric (BQ-IDMS) method with traceability to the International System of Units (SI).

The Martin/Hopkins equation outperforms the Friedewald and Sampson equations by exhibiting the lowest discordance with HSA’s traceable LDL-C reference values. Fewer misclassifications (under-estimations) as compared to the Friedewald equation was particularly observed in samples with higher triglycerides and LDL-C levels. A possible impact of such misclassification was the deferral or withdrawal of therapies, and thus under-treatment of higher risk patients.

The potential adoption of the alternative Martin/Hopkins equation, which is more reliable at higher triglyceride levels, also supports the use of non-fasting lipid tests in Singapore for opportunistic screening, facilitating early detection and medical intervention. The impactful findings were presented by HSA to Singapore’s Ministry of Health in October 2023.

See peer-reviewed scientific paper titled “Evaluation of low-density lipoprotein cholesterol equations by cross-platform assessment of accuracy-based EQA data against SI-traceable reference value” in Clinical Chemistry and Laboratory Medicine, 2023, Apr 4, doi: 10.1515/cclm-2022-1301.