Updating the LDL-C Equation & Lipid Reporting in Ontario Labs

The Ontario Laboratory Medicine Program’s (OLMP) Biochemistry Expert Panel is recommending Ontario clinical biochemistry laboratories update low-densitx`y lipoprotein cholesterol (LDL-C) practices to reflect current best practices and support harmonized reporting, via the following:

Calculate low-density lipoprotein cholesterol (LDL-C) using the Sampson-National Institutes of Health (NIH) equation, instead of the previous Friedewald LDL-C equation; and
Harmonize to the latest lipid reporting best practices (included in table 1)

Background

Lipid panel testing is primarily used in patients to check their lipid status or assess cardiovascular disease risk. A standard lipid panel includes total cholesterol, HDL-cholesterol, LDL-cholesterol, non-HDL-cholesterol, and triglycerides, and can be measured in a fasting or non-fasting state.
Test results will often determine whether a patient requires medications or lifestyle modifications to lower their risk of a heart attack or stroke.
ApoB and lipoprotein(a) are two additional tests that are not part of the standard lipid panel, but can provide important information supporting a patient’s cardiovascular risk assessment. At the moment, lipoprotein(a) is recommended to be measured only once in adulthood.

Rationale

The Friedewald equation, which has traditionally been used to calculate LDL-C, was developed in 1972 and is not valid in patients who have triglycerides > 4.50 mmol/L or have type III hyperlipoproteinemia, and is inaccurate when LDL-C < 1.50 mmol/L. It was also not originally validated for non-fasting patients.
The Sampson-NIH equation ^[1], developed in 2020 and validated in a Canadian cohort ^[2], accurately estimates LDL-C when patients are either fasting or non-fasting, when triglycerides are as high as 9.04 mmol/L, and when LDL-C results are as low as 0.50 mmol/L. February 27, 2026
Harmonizing the way laboratories report lipid testing is essential for accurate, evidence-based decision making for all Ontarians no matter where they live in the province. The below table recommends lipid decision limits and flagging for adults and pediatric patients.
Updated LDL-C equation and recommendations for lipid reporting will align with:
- Canadian Cardiovascular Society (CCS) guidelines for the management of dyslipidemia in adults ^[3]
- The CCS/Canadian Pediatric Cardiology Association recommendations for the management of dyslipidemia children and adolescents ^[4]
- The Canadian Society of Clinical Chemists laboratory lipid reporting recommendations for adults ^[5] and pediatrics ^[6]

Impact to organizations and clinical stakeholders

Patients with triglyceride concentrations between 4.50–9.04 mmol/L will now receive calculated LDL-C results using the Sampson-NIH equation.
The Sampson-NIH LDL-C equation is accurate up to a triglyceride concentration of 9.04 mmol/L. If triglyceride results are above 9.04 mmol/L, an LDL-C result should not be reported. Clinicians should consider non-HDL-C or ApoB testing instead.
Some patients with values < 1.50 mmol/L may see a shift in LDL-C results with the Sampson-NIH equation, due to the inaccuracy of the previous Friedewald equation. LDL-C results are accurate down to 0.50 mmol/L with the Sampson-NIH equation. Results below 0.50 mmol/L should be reported as < 0.50 mmol/L.
Result flagging rates may change as laboratories update their decision limit thresholds. In adults, the LDL-C and non-HDL-C flagging is set for individuals with intermediate cardiovascular risk.

Potential Implementation Risks and Mitigations

The new LDL-C equation is more complex, and requires comprehensive IT testing in both TEST and LIVE environments. The CSCC Toolkit, and reporting tables included in the appendix provide template results and LDL-C calculations to verify the LDL-C equation is setup correctly.
Prior to implementing the Sampson-NIH LDL-C equation, clinical laboratories should utilize existing organization-specific communication channels to alert clinical stakeholders of the change and have a mechanism for feedback. This document can serve as a reference.
It is recommended that laboratory reports include a temporary comment highlighting the change in decision limits and flagging, as well as date of implementation. For example, “Please note the change in decision limits and flagging to align with Ontario Health recommendations. Effective YYYY-MM-DD.”
It is also recommended to include a comment indicating what LDL-C equation is being used on the report. For example, “LDL-cholesterol calculated using the Sampson-NIH LDL-C equation (JAMA Cardiology 2020;5(5):540-548). Effective YYYY-MM-DD.”

New Sampson-NIH LDL-C equation (SI units, mmol/L)

$LDL - C = (\frac{TC}{0.948} - \frac{HDL - C}{0.971} - (\frac{TG}{3.74} + \frac{TG \times Non-HDL-C}{24.16} - \frac{{TG}^{2}}{79.36}) - 0.244$

The equation above should be used for all low-density lipoprotein cholesterol (LDL-C) calculations except in patients with:

Type III hyperlipoproteinemia
Triglycerides > 9.04 mmol/L

Please email us using our contact form to request the Excel file for Key verification conditions and template to verify correct calculation of Sampson-NIH LDL-C Equation.

Table 1. Summary of Lipid Reporting Changes

Test	Adult (≥ 20) normal ranges (mmol/L)^1,3,5	Pediatric (< 20 yo) normal ranges (mmol/L)^4,6
LDL-C (calculated) – NIH equation	< 3.50	Desired: < 2.80 Borderline: 2.80 - < 3.40 Increased risk: ≥ 3.40
Non-HDL-C	< 4.20	Desired: < 3.10 Borderline: 3.10 to < 3.75 Increased risk: ≥ 3.75
Total Cholesterol	< 5.20	Desired: < 4.40 Borderline: 4.40 to < 5.20 Increased Risk: ≥ 5.20
HDL-C	Males: ≥ 1.00 Females: ≥ 1.30	Desired: > 1.20 Borderline: 1.00 to 1.20 Increased risk: < 1.00
Triglycerides	Fasting: < 1.70 Non-fasting: < 2.00	0-9 yo: Fasting: Desired: < 0.80 Borderline: 0.80 to < 1.10 Increased risk: ≥ 1.10 Non-fasting: Desired: < 1.50 mmol/L Borderline: 1.50 - < 2.20 mmol/L Increased risk: ≥ 2.20 mmol/L 10-19 yo: Fasting: Desired: < 1.00 Borderline: 1.00 to < 1.50 Increased risk: ≥ 1.50 Non-fasting: Desired: < 1.50 mmol/L Borderline: 1.50 - < 2.40 mmol/L Increased risk: ≥ 2.40 mmol/L

Other Tests

Test	Adult (≥ 20 yo) normal ranges^1,3,5	Pediatric (< 20 yo) normal ranges^4,6
ApoB	< 1.05 g/L	Desired: < 0.65 g/L Borderline: 0.65 – 0.80 g/L Abnormal: ≥ 0.80 g/L
Lp(a)	< 100 nmol/L	< 100 nmol/L

Please email us using our contact form to request the Excel file with full reporting tables for Lipid Panel, Lp(a) and ApoB testing.

Stakeholder Consultation

The following clinical recommendation was subject to a provincial consultation period where stakeholder feedback was collected and incorporated into this final recommendation.
Consultation included a detailed webinar outlining the proposal with an open question-and-answer period, as well as an online clinical recommendation feedback form where all stakeholders could provide direct feedback related to the clinical recommendation and rationale.
For more information, please contact our program.

[1] Sampson M, et al. A new equation for calculation of low-density lipoprotein cholesterol in patients with normolipidemia and/or hypertriglyceridemia. JAMA Cardiology 2020;5(5):540-548.

[2] Higgins V, et al. Validating the NIH LDL-C equation in a specialized lipid cohort: Does it add up? Clin Biochem. 2022;99:60-68.

[3] Pearson GJ, Thanassoulis G, Anderson TJ, et al. 2021 Canadian Cardiovascular Society Guidelines for the Management of Dyslipidemia for the Prevention of Cardiovascular Disease in Adults. Can J Cardiol. 2021;37(8):1129-1150.

[4] Khoury M, Bigras JL, Cummings EA, et al. The Detection, Evaluation, and Management of Dyslipidemia in Children and Adolescents: A Canadian Cardiovascular Society/Canadian Pediatric Cardiology Association Clinical Practice Update. Can J Cardiol. 2022;38(8):1168-1179.

[5] White-Al Habeeb N & Higgins V, et al. Harmonized Lipid Reporting for Clinical Laboratories based on the 2021 Canadian Lipid Guidelines. Can J Cardiol. 2022;38(8):1180-1188.

[6] Higgins V, White-Al Habeeb NMA, et al. Canadian Society of Clinical Chemists Working Group on Reference Interval Harmonization. Canadian Society of Clinical Chemists Harmonized Pediatric Lipid Reporting Recommendations for Clinical Laboratories. Can J Cardiol. 2024 Jul;40(7):1183-1197.

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Last Updated: September 16, 2026

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