Potential Interferences from Blood Collection Tubes in Mass Spectrometric Analyses of Serum Polypeptides

Abstract

Currently, there are high degrees of both enthusiasm and controversy regarding the potential diagnostic application of matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectrometry (1)(2)(3)(4)(5)(6)(7). This technique permits the simultaneous analysis of a large number of polypeptide components in biological fluids. Greatest sensitivity and resolution are achieved by MALDI TOF mass spectrometry in the mass range from ∼500 to 20 000 Da; this has led to the recognition that there is a highly complex mixture of peptide components in serum that circulate bound to larger proteins (8)(9). The complex patterns of peptide components are very information rich and may contain multiple biomarkers of diagnostic value (1)(2)(3)(4)(5)(6)(7)(8)(9). The present study examined whether different types of blood collection tubes add molecules to specimens that may appear as interfering or confounding peaks during MALDI TOF mass spectrometry. Commercially available blood collection tubes contain multiple components that may shed polymers in the molecular size range of interest. Silicones are commonly used as lubricants for stoppers or coatings for the internal surface of tubes. Polymeric surfactants such as polyvinylpyrrolidones or polyethylene glycols may be added to influence surface wetting. Tubes may contain either clot inhibitors or activators. Serum separator tubes contain polymeric gels with several constituents to adjust viscosity, density, and other physical properties. Rubber stoppers and the plastics comprising tube walls may shed polymeric components or plasticizers. Previous studies have reported effects of blood collection tubes on a variety of laboratory tests (10)(11)(12)(13)(14). These effects can arise from adsorption of serum or plasma components to the tube or separator gel, from the release of materials …