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Published on: November 17, 2011
Reference standardization and analytical performance of a liquid homogeneous high-density lipoprotein cholesterol
P Halloran1, H Roetering, T Pisani
1Diagnostics Research and Development, Genzyme Diagnostics, Cambridge, Mass 02139, USA.
Insights
The Liquid N-geneous (LN-gen) HDL-C assay provides accurate and precise high-density lipoprotein cholesterol measurements. This cost-effective method meets National Cholesterol Education Program guidelines for clinical use.
Area of Science:
- Clinical Chemistry
- Biomarker Measurement
- Cardiovascular Disease Risk Assessment
Background:
- Accurate high-density lipoprotein cholesterol (HDL-C) measurement is crucial for assessing coronary heart disease risk.
- Traditional reference (RM) and designated comparison (DCM) methods for HDL-C are complex and costly for routine use.
- The Liquid N-geneous (LN-gen) assay was developed as a homogeneous reagent for HDL-C determination.
Purpose of the Study:
- To evaluate the accuracy and precision of the LN-gen HDL-C assay.
- To determine if the LN-gen assay meets the National Cholesterol Education Program (NCEP) requirements.
- To compare the LN-gen assay with established RM and DCM methods.
Main Methods:
- The LN-gen HDL-C assay was compared against the DCM for normotriglyceridemic samples (< 2.0 g/L triglycerides).
- Comparison with the RM was performed for samples with elevated triglycerides (≥ 2.0 g/L).
- Accuracy was assessed using linear regression, bias analysis, and correlation coefficients.
Main Results:
- The LN-gen assay demonstrated strong correlation with both DCM (r = 0.993) and RM (r = 0.985).
- Mean percent bias for LN-gen was 3.3% to DCM and 1.5% to RM, showing good agreement.
- Precision was excellent (< 2.1% coefficient of variation) with total error ≤ 7.7% at critical decision points.
Conclusions:
- The LN-gen HDL-C assay is a convenient and cost-effective method for measuring HDL-C.
- The assay meets the NCEP's 1998 recommendations for precision, bias, and total error.
- LN-gen assay is suitable for routine clinical laboratory use in HDL-C evaluation.
Background:
The use of high-density lipoprotein cholesterol (HDL-C) levels as a risk factor for coronary heart disease necessitates an accurate and precise method for measuring HDL-C. The Centers for Disease Control and Prevention HDL-C reference method (RM) and designated comparison method (DCM) are time-consuming, expensive, and impractical for routine clinical use. We evaluated the Liquid N-geneous (LN-gen) HDL-C assay (Genzyme Diagnostics, Cambridge, Mass) to determine if this homogeneous reagent meets the National Cholesterol Education Program requirements for HDL-C evaluation.
Design:
Accuracy of the LN-gen HDL-C assay was compared in combination with phosphotungstic acid (PTA) precipitation with DCM HDL-C for normotriglyceridemic serum specimens (triglycerides < 2.0 g/L) and with RM HDL-C for specimens with triglycerides levels > or = 2.0 g/L.
Setting:
Genzyme Diagnostics (with RM and DCM assayed by Pacific BioMetrics Inc, Seattle, Wash) and the Lipid Reference Laboratory of the University Hospital Rotterdam, The Netherlands.
Results:
Linear regression to DCM (n = 90) was (LN-gen = 1.015 DCM + 0.01 g/L, r = 0.993, SE = 0.015 g/L) and (PTA = 1.004 DCM - 0.017 g/L, r = 0.980, SE = 0.025 g/L), with a mean percent bias to DCM of 3.3% and -2.8% for LN-gen and PTA, respectively. The comparison with RM (n = 69) showed an increased mean bias for PTA (-5.8%) as compared with LN-gen (1.5%). The correlation and regression equations were (LN-gen = 1.020 RM - 0.002 g/L, r = 0.985, SE = 0.017 g/L) and (PTA = 1.042 RM - 0.032 g/L, r = 0.984, SE = 0.018 g/L). The precision of LN-gen was confirmed at < 2.1% coefficient of variation, and the total error was calculated to be < or = 7.7% for both normotriglyceride and elevated triglyceride specimens at HDL-C decision points of 0.35 g/L and 0.60 g/L.
Conclusions:
The LN-gen HDL-C assay offers a cost-effective convenient method for meeting the 1998 precision, bias, and total error recommendations of the National Cholesterol Education Program.
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