Graham Jones commented "...The correlation of the lipaemia index (on Hitachi) with amounts of triglycerides is poor, especially at relatively low concentrations (eg TG<10 mmol/L) and this is indicated by Roche in their literature. ..."
This is true in my experience too. For a specific project in which lipemia and/or turbidity was an important issue, I recently set up a semiquantitative "turbidity index" by printing a series of numbers (0-9) with increasing pixel density and determining the smallest number I could make out through the serum/plasma in a standard tube size (the old read through estimate). Each sample was assayed for triglyceride and serum indices. Interestingly, the lipemia (L) index correlated fairly well with the "T-index," but correlated very poorly with triglyceride. In addition, the T-index (and L-index) were much better than triglyceride at predicting interference in the assay under study.
I'm not sure how to explain this though. Are there other components of serum or plasma besides lipoproteins (thus triglycerides) that cause turbidity? Or is the variability of triglycerides in lipoproteins relative to their ability to scatter light so great that triglyceride is not a good measure of lipoprotein induced turbidity?
-Jim
James J Miller, Ph.D., DABCC, FACB
Associate Professor
Dept. of Pathology & Laboratory Medicine
University of Louisville
Louisville, KY 40292
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502-852-1179
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