Laboratory diagnostics (i.e., the total testing process) develops conventionally through a virtual loop, originally referred to as ''the brain to brain cycle'' by George Lundberg. Throughout this complex cycle, there is an inherent possibility that a mistake might occur. According to reliable data, preanalytical errors still account for nearly 60%-70% of all problems occurring in laboratory diagnostics, most of them attributable to mishandling procedures during collection, handling, preparing or storing the specimens. Although most of these would be ''intercepted'' before inappropriate reactions are taken, in nearly one fifth of the cases they can produce inappropriate investigations and unjustifiable increase in costs, while generating inappropriate clinical decisions and causing some unfortunate circumstances. Several steps have already been undertaken to increase awareness and establish a governance of this frequently overlooked aspect of the total testing process. Standardization and monitoring preanalytical variables is of foremost importance and is associated with the most efficient and well-organized laboratories, resulting in reduced operational costs and increased revenues. As such, this article is aimed at providing readers with significant updates on the total quality management of the preanalytical phase to endeavour further improvement for patient safety throughout this phase of the total testing process.

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The BD Vacutainer PST II Tube provided clinically equivalent results to serum and plasma non-gel tubes and good storage stability for the assays evaluated without the need to aliquot.

Technical performance and data management features are prominent criteria in the selection of an appropriate meter for a point-of-care glucose testing program. We evaluated the technical performance of 5 currently available glucose meters with data management capabilities. The performance of all 5 meters was technically equivalent. Linear regression slopes vs the reference method are in the range of 0.94 to 1.02 and indicate correlation more to plasma values than to whole blood values. The percentage of glucose meter results within +/- 15% of the laboratory value was at least 90%; however, the percentage within +/- 10% was 75% to 87% for most meters. Within-day and between-day precision ranged from 2% to 5% coefficient of variation. Evaluation of linearity with glucose-spiked venous specimens demonstrated that the linearity of each meter agreed with the manufacturer's stated range in most cases. Meter glucose values tended to bias negative as the hematocrit increased, an effect that may be more pronounced at higher glucose concentrations. No volume effects were noted between 5 microL and 40 microL. The results suggest that all meters tested will likely satisfy technical performance criteria in a hospital setting and that selection of a system for point-of-care glucose testing will be influenced by the institution's data management requirements.

Background: Hemoglobin-based oxygen carriers can cause profound interferences in many analytical procedures. We determined the mechanism of interference in the assay of alkaline phosphatase activity and identified approaches that might be used to correct for this interference. Methods: Interference of a polymerized hemoglobin blood substitute with the assay of alkaline phosphatase was examined with a Hitachi 917 analyzer and ultraviolet-visible spectrophotometry. Results: Hemoglobin-based oxygen carrier solutions had substantial absorbance at 415 nm, the wavelength of analysis used to measure the formation of 4-nitrophenol. In addition to offsetting the initial absorbance at the analytical wavelength, polymerized hemoglobin gave rise to a strong negative interference plot because of alkali denaturation of the substitute. The same interference mechanism was also observed for native hemoglobin (hemolysate), indicating that the interference was not derived from the polymerization process. The interference can be corrected by implementing a rate-correction procedure, or the interference can be avoided by measurement at 450 nm. Conclusions: The interference of polymerized hemoglobin in the alkaline phosphatase assay is a result of an absorbance offset caused by alkali denaturation of hemoglobin. The interference can be corrected or avoided by modifying the calculation or the analytical wavelength. The correction strategy may also be applicable to improving the hemolysis index for this method.

The SenDx 100 portable blood gas and electrolyte analyzer is a simple and easy to use analyzer demonstrating acceptable performance compared with reference methods.

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