SAMPLE PREPARATION FOR POINT-OF-CARE ASSAYS WITH WHOLE BLOOD SAMPLES

Abstract

In recent decades, significant advances have been made in diagnostics, particularly point-of-care diagnostics. Most of these advances have focused on the analytical steps of diagnostics rather than the pre-analytical steps. The pre-analytical steps include sample collection, transit, storage, and sample preparation, with most of these being process issues. However, sample preparation is often an overlooked step in the pre-analytical phase that contributes to the turnaround time of diagnostic assays. Laboratory assays often have long turnaround times because they rely on sample preparation in a central laboratory, whereas point-of-care assays could offer a more rapid alternative. Upon review of the literature, many proposed point-of-care assays are not truly point-of-care, nor are they as rapid as they should be when using blood as the sample, since they rely on blood-sample preparation steps that require central laboratories. To truly be point-of-care, whole-blood sample preparation should ideally be performed without requiring central laboratory equipment or personnel, with plasma or serum separation integrated into the point-of-care assay. Three novel whole blood sample preparation strategies are reported in this thesis. Each technique uses a different primary mechanism. The first technique uses agglomeration agents to promote red blood cell removal for optically based homogeneous assays. The second technique uses a two-stage filter cassette to convert blood to serum for fluorescence assays. Finally, the third strategy uses acid digestion and filtration to lyse red blood cells and coagulate debris for point-of-care lead testing. These blood microsample preparation methods, through their simple operation and rapid conversion of whole blood to a prepared sample, have the potential to greatly advance the pre-analytical phase of point-of-care assays.