Each technology has its selleck own advantages and limitations. For example, researchers use two-dimensional gel electrophoresis-MS for plasma biomarker analysis because of its remarkable resolving power, increased sensitivity and high throughput proteome analysis capabilities [37,45], and although this technology is usually accessible to most of the researchers, it is laborious and not applicable for small and hydrophobic peptides. In addition there is a limited dynamic range for quantitative measurement. Recent studies have been exploring liquid chromatography-MS because it requires only small amounts of sample and is highly sensitive. Complex quantification analysis and sensitivity for interfering compounds are the drawbacks for this technique.

Surface enhanced laser desorption/ionization-time of flight MS is a newly introduced protein identification technique with better resolution and quantification and selective capture of proteins under native conditions, although the post-processing is a complex procedure and reproducibility is still problematic. Enzyme-linked immunosorbent assay (ELISA) is one of the major proteomic techniques used worldwide for quantification of proteins but the major disadvantage is the availability of specific antibodies. Table 1 Summary of some recent multiplex Alzheimer’s disease biomarker studies Challenges associated with standardization and validation of the results Although an overwhelming volume of research has been done in the field of AD blood biomarkers so far, there is a clear lack of reproducibility of the results obtained across different studies.

Firstly, differing methods of collection, transport and storage of samples may be one of the reasons for the observed differences. AIBL study protocol involves overnight fasting for the participants; the same is not the case, however, for other well characterized cohorts such as the Texas Alzheimer’s Research and Care Consortium (TARCC). Long-term storage of the samples in Carfilzomib liquid nitrogen versus -80??C following website freezer has an impact on the levels of certain protein biomarkers. Secondly, variations among the assay and interpretation methods could be another factor. Changes in the biomarker panel have been observed when alternative methods are used (for example, MS versus ELISA). Thirdly, selection criteria of the cohort could be another important factor. The participants recruited in different studies might be at different stages of disease pathology though the clinical symptoms are still concealed.