Related Experiment Video
Updated: Jun 18, 2026
07:29
Cell-free Biochemical Fluorometric Enzymatic Assay for High-throughput Measurement of Lipid Peroxidation in High Density Lipoprotein
Published on: October 12, 2017
9.4K
Lipid Ratio Plot: A Simple Graphical Approach for Investigating the Accuracy of LDL Cholesterol Equations or Direct
Thando Gcingca1, Maureen Sampson1, Rafael Zubirán2
1Department of Laboratory Medicine, Clinical Center, National Institutes of Health, Bethesda, MD, United States.
The Journal of Applied Laboratory Medicine
|July 23, 2025
Summary
A new lipid ratio plot method accurately assesses low-density lipoprotein cholesterol (LDL-C) test results against the reference method. This graphical approach helps clinical labs evaluate LDL-C assay accuracy, especially when the reference method is unavailable.
Area of Science:
- Clinical Chemistry
- Biomarker Measurement
- Laboratory Diagnostics
Background:
- Beta-quantification (BQ) is the gold standard for low-density lipoprotein cholesterol (LDL-C) measurement but is not widely accessible.
- Clinical laboratories face challenges in verifying the accuracy of routine LDL-C assays due to the limited availability of the BQ reference method.
Purpose of the Study:
- To develop and validate an indirect graphical method for comparing LDL-C results from various assays to the BQ reference method.
- To establish a practical tool for laboratories to assess LDL-C assay accuracy without direct access to BQ.
Main Methods:
- Utilized large datasets (n=39,969 and n=17,825) of lipid panel results from Mayo Medical Laboratories and the National Institutes of Health.
- Developed a 'lipid ratio plot' by plotting LDL-C/non-high-density lipoprotein cholesterol (nonHDL-C) against the square root of the triglyceride (TG)/nonHDL-C ratio.
- Determined the minimum sample size (n=80) required for reliable slope and intercept calculations with a 7.5% coefficient of variation.
Main Results:
- The lipid ratio plot demonstrated excellent agreement with the BQ method for LDL-C calculated using Sampson-NIH and enhanced Sampson-NIH equations.
- The Martin-Hopkins and Friedewald equations showed increasing biases with hypertriglyceridemia, exceeding acceptable limits.
- Direct assays from Roche exhibited a fixed positive bias, while Beckman assays showed a proportional positive bias that increased with triglyceride levels.
Conclusions:
- The lipid ratio plot is a straightforward and effective graphical tool for clinical laboratories.
- This method allows for the assessment of LDL-C assay accuracy, including both calculation-based and direct methods, against the BQ reference standard.
- It provides a valuable alternative for laboratories lacking direct access to the BQ method for LDL-C validation.
