Search

Introduction: A product recall was issued for the Roche/Hitachi Cobas Gentamicin II assays on 25th May 2016 in Australia, after a 15 - 20% positive analytical shift was discovered. Laboratories were advised to employ the Thermo Fisher Gentamicin assay as an alternative. Following the reintroduction of the revised assay on 12th September 2016, a second reagent recall was made on 20th March 2017 after the discovery of a 20% negative analytical shift due to erroneous instrument adjustment factor. Materials and methods: The practices of an index laboratory were examined to determine how the analytical shifts evaded detection by routine internal quality control (IQC) and external quality assurance (EQA) systems. The ability of the patient result-based approaches, including moving average (MovAvg) and moving sum of outliers (MovSO) approaches in detecting these shifts were examined. Results: Internal quality control data of the index laboratory were acceptable prior to the product recall. The practice of adjusting IQC target following a change in assay method resulted in the missed negative shift when the revised Roche assay was reintroduced. While the EQA data of the Roche subgroup showed dear negative bias relative to other laboratory methods, the results were considered as possible 'matrix effect'. The Mo-vAvg method detected the positive shift before the product recall. The MovSO did not detect the negative shift in the index laboratory but did so in another laboratory 5 days before the second product recall. Conclusions: There are gaps in current laboratory quality practices that leave room for analytical errors to evade detection. [ABSTRACT FROM AUTHOR]

Background: Recently, the total prostate-specific antigen (PSA) assay used in a laboratory had a positive bias of 0.03 µg/L, which went undetected. Consequently, a number of post-prostatectomy patients with previously undetectable PSA concentrations (defined as < 0.03 µg/L in that laboratory) were being reported as having detectable PSA, which suggested poorer prognosis according to clinical guidelines. Methods: Through numerical simulations, we explored (1) how a small bias may evade the detection of routine quality control (QC) procedures with specific reference to the concentration of the QC material, (2) whether the use of 'average of normals' approach may detect such a small bias, and (3) describe the use of moving sum of number of patient results with detectable PSA as an adjunct QC procedure. Results: The lowest QC level (0.86 µg/L) available from a commercial kit had poor probability (< 10%) of a bias of 0.03 µg/L regardless of QC rule (i.e. 1 : 2S, 2 : 2S, 1 : 3S, 4 : 1S) used. The average number of patient results affected before error detection (ANPed) was high when using the average of normals approach due to the relatively wide control limits. By contrast, the ANPed was significantly lower for the moving sum of number of patient results with a detectable PSA approach. Conclusions: Laboratory practitioners should ensure their QC strategy can detect small but critical bias, and may require supplementation of ultra-low QC levels that are not covered by commercial kits with in-house preparations. The use of moving sum of number of patient results with a detectable result is a helpful adjunct QC tool. [ABSTRACT FROM AUTHOR]

We describe the synthesis and characterizationof three new alternatingcopolymers containing fluorene and a dually dopable benzimidazolemoiety. Poly(2-n-heptyl-benzimidazole-alt-9,9-di-n-octylfluorene) (PBIF), poly(2-n-heptyl-benzimidazole-vinylene-9,9-di-n-octylfluorene) (PBIF-VL), and poly(2-n-heptyl-benzimidazole-ethynylene-9,9-di-n-octylfluorene)(PBIF-EL) were synthesized from Suzuki, Heck, and Sonogashiracross-coupling reactions in reasonable yield. The materials were characterizedthrough ultraviolet–visible spectroscopy, photoluminescence,and cyclic voltammetry. The vinyl and ethynyl bridges in PBIF-VLand PBIF-ELwere incorporated to separate benzimidazoleand fluorene units while retaining conjugation. This allowed us todifferentiate between steric and electronic contributions to the bandgap (Eg) changes that occur upon acid/basedoping of these materials. We demonstrate that the blue shift arisingfrom acid doping PBIFis due to steric torsion, whilethe red shift found upon base doping PBIFis due to bothsterics and possibly an electronic effect. These findings are supportedthrough the use of molecular modeling. [ABSTRACT FROM AUTHOR]