[Potential Interferences from Blood Collection Tubes in Mass Spectrometric Analyses of Serum Polypeptides]
Clinical Chemistry 50: 2398-2401, 2004; 10.1373/clinchem.2004.040303
Technical Briefs
Potential Interferences from Blood Collection Tubes in Mass Spectrometric Analyses of Serum Polypeptides
Steven K. Drake1, Raffick A.R. Bowen2, Alan T. Remaley2 and Glen L. Hortin2,a
Departments of1 Critical Care Medicine and2 Laboratory Medicine, Warren Magnuson Clinical Center, NIH, Bethesda, MD
aaddress correspondence to this author at: Department of Laboratory Medicine, NIH, Bldg. 10, Room 2C-407, Bethesda, MD 20892-1508; fax 301-402-1885, e-mail ghortin@mail.cc.nih.gov
The first 300 words of the full text of this article appear below.
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 . . . <<
>>Clinical Chemistry 51: 3-5, 2005; 10.1373/clinchem.2004.043281
Editorials
Can Mass Spectrometric Protein Profiling Meet Desired Standards of Clinical Laboratory Practice?
Glen L. Hortin
Department of Laboratory Medicine, Warren Magnuson Clinical Center, NIH, Bldg. 10, Room 2C-407, Bethesda, MD 20892-1508, Fax 301-402-1885, E-mail ghortin@mail.cc.nih.gov
The first 20% of the full text of this article appears below.
This issue of Clinical Chemistry contains a report describing interlaboratory comparison of a prostate cancer test based on profiling of serum proteins by mass spectrometry (1). This report is relevant to the recent controversy regarding the diagnostic potential and reliability of this approach to the diagnosis of cancer or other diseases (2)(3)(4)(5)(6)(7)(8). This controversy has raised questions regarding whether mass spectrometric profiling of proteins can achieve standards of reproducibility and performance that are expected of clinical tests. Semmes et al. (1) examine whether different laboratories can achieve equivalent results on split specimens. These efforts are commendable starts to issues of standardization, calibration, and quality control (QC), all important elements in the transition of this technology from the discovery phase to clinical application. However, their report also exemplifies how initial efforts to apply this technology have not yet met the desired standards of clinical laboratory practice.
Although proteomic profiling has provided breakthroughs in the discovery of new disease markers, initial discovery methods generally have been poorly suited for clinical applications. Marker discovery methods typically have not incorporated principles applied to existing clinical laboratory applications of profiling methods, such as serum protein electrophoresis, amino acid analyses, or tandem mass spectrometric screening for inborn errors. Some lessons from clinical experience include the importance of (a) use of internal standards for mass spectrometry, (b) identifying measured components, (c) developing standards for calibration and QC, (d) identifying peaksets in spectra, and (e) applying established standards for method evaluation (9), e.g., measures of reproducibility, detection limits, linearity, and recovery; evaluation of calibration curves, potential interferences, reference intervals, and peak characteristics; and . . . <<
The article being referred to here is this one:
Message 20884932
Which happens to be the one Matt Hogan mentioned last October as being an important paper regarding reproducibilty.
Message 20618524
Important indeed, but hardly puts the issue to rest, and thus the stock is where it is: still near lows pending a pick up in sales.
Cheers, Tuck |
