Ultracentrifugation as a tool for removal of interference caused by lipemia in liver function test

Abstract

Introduction: Very often in clinical biochemistry laboratory, lipemic samples are encountered which causes analytical interference in measurement of various biochemistry parameters. In routine practice, 8 to 10 hours of fasting is advised to overcome interference caused by lipemia. To minimize lipemic interference ultracentrifugation, high speed centrifugation, lipid clearing agent, dilution with normal saline or sample blanking can be used. Out of these, u ltracentrifugation is likely to cause least interference as there is minimal exposure to additional chemicals. Aims and Objectives: Aims and objectives of the study were to, identify lipemic samples, analyze liver function test in lipemic samples before ultracentrifugation, perform ultracentrifugation, analyze same analytes after ultracentrifugation and compare the results for any significant statistical and clinical difference. Materials and Methods: From 50 lipemic samples, 2 aliquots were prepared each having 500 microliter of serum. One aliquot was used to perform liver function test. Second aliquot was further subjected to the ultracentrifugation after which the same biochemical parameters were performed. Comparison of results obtained, was done by paired Student’s t-test in Microsoft Office 2007 to assess statically significant difference. Ratio of (lipemic bias in relation to ultracentrifuge samples) to (Biological Variation, CLIA acceptability criteria and laboratory CV %) were also calculated to see whether the difference is clinically significant or not. Results: Statistically significant difference between lipemic and ultracentrifuge samples was observed in alkaline phosphatase, alanine transaminase, total bilirubin, albumin and total protein while only total bilirubin, total protein and alanine transaminase showed clinically significant difference. Conclusions: Ultracentrifugation results in statistically significant difference in results obtained for all parameters of liver function test but clinic