Biological variability of blood omega-3 biomarkers

Objectives: We conducted a pilot study to estimate the biological variability and effects of a prior meal on the omega-3 fatty acid (FA) content of 3 blood FA pools. Design and methods: We measured FA levels in red blood cells (RBCs), plasma and plasma phospholipids (PL) obtained from 20 healthy volunteers tested weekly over 6 weeks. Results: The within-subject coefficients of variation were 4.1% +/- 1.9%, 15.9% +/- 6.4%, and 14.5% +/- 8.4%, respectively (RBC vs. others, p<0.001). RBC omega-3 FA content had the lowest biological variability and was not altered in the fed state. Conclusions: From the perspective of variability and of the sample types tested, RBCs may be the preferred sample type for assessing omega-3 FA status. (C) 2009 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.