Poster Presentation ESA-SRB 2023 in conjunction with ENSA

What's new with LDL-cholesterol calculations? (#223)

Caroline Bachmeier 1 , Timothy Foster 1 , Gemma Daley 1 , Robert Flatman 1 , Lee Price 1 , David Kanowski 1 , Greg Ward 1
  1. Chemical Pathology, Sullivan Nicolaides Pathology, Bowen Hills, QLD, Australia

LDL-cholesterol is a major risk factor for cardiovascular disease and is still a major target in clinical practice guidelines. 1 While the gold standard for lipid measurement is beta-quantification this is expensive, labour-intensive and not practical for routine use. Instead most laboratories use the Friedewald formula to calculate LDL-cholesterol. 2 This comes with several limitations, including inaccuracy when triglycerides are greater than 4.5 mmol/L, the presence of chylomicrons or IDL-cholesterol or very low LDL-cholesterol values. 3 Various new calculations have been developed, with the Sampson equation being a promising alternative to the Friedwald equation, allowing calculation of LDL-cholesterol with triglycerides up to 9 mmol/L and showing a significantly better correlation to gold standard methods. 4 We applied the Sampson equation to a local dataset of 337,138 patient samples with calculated LDL-cholesterol results via the Friedewald formula. The Sampson equation showed excellent correlation with the Friedewald formula for triglycerides < 4.5 mmol/L, but additionally allowed calculation of of LDL-cholesterol in cases of triglycerides 4.5 - 9 mmol/L. In our laboratory this will result in the ability to provide calculated LDL-cholesterol results for an additional 2% of patients (or 18,826 samples per year).