Discrepancies in Lipemia Interference Between Endogenous Lipemic Samples and Smoflipid-Supplemented Samples.

Background: Manufacturers evaluate lipemia-induced interference using Intralipid, but it does not contain all lipoprotein types. The aim of this study was to evaluate lipemiainduced interference in biochemical parameters from endogenous lipemic samples and SMOFlipid supplemented samples, in order to assess if SMOFlipid can be used in lipemic interference studies.

Methods: Serum pools were supplemented with SMOFlipid to achieve 800 mg/dL and 1500 mg/dL triglyceride concentration, and analyzed for 25 biochemical parameters both before and after the supplementation. In another independent phase, lipemic serum pools were prepared choosing patient samples of 800 mg/dL and 1500 mg/dL triglyceride concentration. These lipemic serum pools were ultracentrifugated in order to remove lipids. Biochemical parameters were analyzed before and after ultracentrifugation. The bias between SMOFlipid-supplemented samples and endogenous lipemic samples were compared. The bias between the lipemic and non-lipemic samples were compared with the reference change value.

Results: At 800 mg/dL triglyceride concentration, we found that total protein and transferrin had been affected only in endogenous lipemic serum samples. Magnesium and creatinine had been affected only in SMOFlipid-supplemented samples. At 1500 mg/dL triglyceride concentration, we found that total protein, amylase, ferritin and glucose had lipemic interference only in endogenous lipemic samples, and chloride only in SMOFlipid-supplemented samples.

Conclusions: The use of SMOFlipid-supplemented samples does not provide suitable data to estimate lipemia-induced interference. Thus, interference studies should be performed using a wide variety of lipemic patient samples that represent the heterogeneity of the lipoprotein particles size.