Comparison of triglyceride concentration with lipemic index in disorders of triglyceride and glycerol metabolism.

In plasma, triglycerides (TG) are transported in lipoprotein particles (mainly chylomicrons, very low-density and low-density lipoprotein). Turbidimetry (bichromatically at 660 and 700 nm) allows measurement of the lipemic (L) index. We explored the use of this index, in combination with a TG assay, to detect errors due to non-fasting, to assess abnormalities in TG metabolism and to detect patients with glycerol kinase deficiency (GKD). We collected 2441 patient samples. Normolipidemic (n=2347), type IV hyperlipidemic (n=80), postprandial samples (n=22) and serial dilutions of Intralipid with saline (n=6) were selected. One patient presenting with GKD was included, as well as two patients with type I and type V hyperlipoproteinemia, respectively. We introduced the use of the ratio between the logarithm of serum triglycerides and that of the L-index (TG/L ratio). Although the proposed TG/L-index ratio cannot be regarded as an alternative for the accurate diagnosis of lipid disorders, it provides additional information about TG-containing particles.