Changes to lipid reporting and the LDL-C equation in Alberta
November 16, 2023
On November 5, 2023, clinical laboratories across the province made changes to lipid result reporting and the LDL-C calculation using the National Institute of Health (NIH) equation rather than Friedewald equation. Included are new flagging limits and laboratory comments for adults. These changes align with Canadian Society of Clinical Chemists (CSCC) recommendations1, which are based on the 2021 Canadian Cardiovascular Society (CCS) Dyslipidemia Guidelines2 and aim to promote lipid harmonization across Canada.
New flagging limits for LDL-C, non-HDL-C and apolipoprotein B are based on lipid screening thresholds in the primary prevention setting for intermediate-risk and select low-risk patients. New laboratory comments refer to the 2021 CCS guidelines for additional thresholds, state limitations of LDL-C when triglycerides are elevated and include a link to ‘Let's Talk Cholesterol ’, an online tool designed by patients and physicians to offer patient resources and a physician guide to facilitate cholesterol management.
The NIH LDL-C equation was validated in various Canadian populations, including in Alberta.3,4,5 The NIH and Friedewald equations compare well for most patients, but the NIH more strongly correlates with the LDL-C reference method (β-quantification) with elevated triglycerides (4.52-9.04 mmol/L) and reduced LDL-C (0.50-1.50 mmol/L). This will avoid cancelled testing for a subset of patients, particularly those with elevated triglycerides.
Refer to the bulletin for more information.
References
- White-Al Habeeb, N, et al., Can J Cardio 38 (2022); 1180-1188
- Pearson GJ, et al., Can J Cardio 37 (2021); 1129-1150
- Higgins V, et al., Clin Biochem 99 (2022); 60-68
- Zhao PJ, et al., CJC Open 5 (2022):37-42
- Higgins V, et al., Clin Biochem (2023) – article in press
