Specific immunofluorimetric assay detecting the chemotactic epitope of the urokinase receptor (uPAR).

The urokinase plasminogen activator receptor (uPAR) fragments D1 and D2D3 are often found in biological fluids from normal individuals and patients of cancer and other diseases. The D2D3 fragment may possess chemotactic activity depending on its N-terminal sequence. We have developed a sensitive and specific immunoassay for the chemotactic form of D2D3 and show that its level can be measured with high specificity and sensitivity in human serum and urine. Synthetic peptides (residues 84-92) derived from the linker region between domains 1 and 2 of uPAR were used as immunogens to generate mouse monoclonal antibodies. Recombinant soluble uPAR (D1D2D3(1-277)) was used to immunize rabbits to obtain polyclonal antibodies. A sandwich-type immunofluorimetric assay was developed with these antibodies. The assay specifically measures D2D3 containing the 84-88 residues, has a detection limit of 0.25 ng/ml and shows no cross-reactivity with D2D3(93-274). The assay is linear at 0-30 ng/ml, with an intra-assay CV of 10% (n=20), inter-assay CV of 15% (n=9) and a recovery of D2D3(84-274) added to urine samples of between 94% and 105%. A statistically significant difference level of D2D3(84-274) was found in two groups of tumor patients versus healthy volunteers (p

Molecular diagnostics by microelectronic microchips.

Molecular diagnostics is being revolutionized by the development of highly advanced technologies for DNA and RNA testing. One of the most important challenges is the integration of microelectronics to microchip-based nucleic acid technologies. The specific characteristics of these microsystems make the miniaturization and automation of any step of a molecular diagnostic procedure possible. This review describes the application of microelectronics to all the processes involved in a genetic test, particularly to sample preparation, DNA amplification and sequence variation detection.

Single-nucleotide polymorphism and mutation identification by the nanogen microelectronic chip technology.

The present chapter describes a microarray technology developed by Nanogen Inc., for the identification of DNA variations based on the use of microelectronics. The NMW 1000 NanoChip Molecular Biology Workstation allows the active deposition and concentration of charged biotinylated molecules on designated test sites. The DNA at each pad is then hybridized with specific oligonucleotide probes, complementary to normal or mutant sequences, that labeled with Cy3 or Cy5 dyes, respectively. The array is imaged, and fluorescence signals are scanned, monitored, and quantified by highly developed, digital image-processing procedures. The experimental steps to be performed for the development and execution of a microchip assay are described. Attention is focused on the fundamental aspects of probe design, and guidelines and useful suggestions are given. Protocols for sample preparation, addressing, reporting, and data analysis are also detailed.

Causes, consequences, detection, and prevention of identification errors in laboratory diagnostics.

Laboratory diagnostics, a pivotal part of clinical decision making, is no safer than other areas of healthcare, with most errors occurring in the manually intensive preanalytical process. Patient misidentification errors are potentially associated with the worst clinical outcome due to the potential for misdiagnosis and inappropriate therapy. While it is misleadingly assumed that identification errors occur at a low frequency in clinical laboratories, misidentification of general laboratory specimens is around 1% and can produce serious harm to patients, when not promptly detected. This article focuses on this challenging issue, providing an overview on the prevalence and leading causes of identification errors, analyzing the potential adverse consequences, and providing tentative guidelines for detection and prevention based on direct-positive identification, the use of information technology for data entry, automated systems for patient identification and specimen labeling, two or more identifiers during sample collection and delta check technology to identify significant variance of results from historical values. Once misidentification is detected, rejection and recollection is the most suitable approach to manage the specimen.

Haemolysis: an overview of the leading cause of unsuitable specimens in clinical laboratories.

Prevention of medical errors is a major goal of healthcare, though healthcare workers themselves have not yet fully accepted or implemented reliable models of system error, and neither has the public. While there is widespread perception that most medical errors arise from an inappropriate or delayed clinical management, the issue of laboratory errors is receiving a great deal of attention due to their impact on the quality and efficiency of laboratory performances and patient safety. Haemolytic specimens are a frequent occurrence in clinical laboratories, and prevalence can be as high as 3.3% of all of the routine samples, accounting for up to 40%-70% of all unsuitable specimens identified, nearly five times higher than other causes, such as insufficient, incorrect and clotted samples. This article focuses on this challenging issue, providing an overview on prevalence and leading causes of in vivo and in vitro haemolysis, and tentative guidelines on identification and management of haemolytic samples in clinical laboratories. This strategy includes continuous education of healthcare personnel, systematic detection/quantification of haemolysis in any sample, immediate clinicians warning on the probability of in vivo haemolysis, registration of non-conformity, completing of tests unaffected by haemolysis and request of a second specimen for those potentially affected.

Process and risk analysis to reduce errors in clinical laboratories.

BACKGROUND: An important point in improving laboratory quality is the definition of some indicators to be monitored as measures of a laboratory trend. The continuous observation of these indicators can help to reduce errors and risk of errors, thus enhancing the laboratory outcome. In addition, the standardization of risk evaluation techniques and the definition of a set of indicators can eventually contribute to a benchmarking process in clinical laboratories. METHODS: Five Italian hospital laboratories cooperated in a project in which methodologies for process and risk analysis, usually applied in fields other than healthcare (typically aeronautical and transport industries), were adapted and applied to laboratory medicine. The collaboration of a board of experts played a key role in underlining the limits of the proposed techniques and adapting them to the laboratory situation. A detailed process analysis performed in each center was the starting point, followed by risk analysis to evaluate risks and facilitate benchmarking among the participants. RESULTS AND CONCLUSIONS: The techniques applied allowed the formulation of a list of non-conformities that represented risks of errors. The level of risk related to each was quantified and graphically represented for each laboratory to identify the risk area characteristic for each of the centers involved.

Laboratory network of excellence: enhancing patient safety and service effectiveness.

Clinical laboratories have undergone major changes due to technological progress and economic pressure. While costs of laboratory testing continue to be the dominant issue within the healthcare service worldwide, quality, effectiveness and impact on outcomes are also emerging as critical value-added features. Five Italian laboratories are therefore promoting a network of excellence by investigating markers of effectiveness of laboratory services and sharing their experience of using them in clinical practice. In the present study we report preliminary data on indicators of quality in all phases of the so-called total testing process, the key to evaluating all phases of the total testing process, including the appropriateness of test requests and data interpretation. Initial findings in evaluating pre-analytical causes of specimen rejection in three different laboratories and the effects of introducing three laboratory clinical guidelines are reported. These data should stimulate debate in the scientific community and encourage more clinical laboratories to use the same indicators to improve clinical effectiveness and clinical outcomes within the healthcare service.

Errors in laboratory medicine.

BACKGROUND: The problem of medical errors has recently received a great deal of attention, which will probably increase. In this minireview, we focus on this issue in the fields of laboratory medicine and blood transfusion. METHODS: We conducted several MEDLINE queries and searched the literature by hand. Searches were limited to the last 8 years to identify results that were not biased by obsolete technology. In addition, data on the frequency and type of preanalytical errors in our institution were collected. RESULTS: Our search revealed large heterogeneity in study designs and quality on this topic as well as relatively few available data and the lack of a shared definition of "laboratory error" (also referred to as "blunder", "mistake", "problem", or "defect"). Despite these limitations, there was considerable concordance on the distribution of errors throughout the laboratory working process: most occurred in the pre- or postanalytical phases, whereas a minority (13-32% according to the studies) occurred in the analytical portion. The reported frequency of errors was related to how they were identified: when a careful process analysis was performed, substantially more errors were discovered than when studies relied on complaints or report of near accidents. CONCLUSIONS: The large heterogeneity of literature on laboratory errors together with the prevalence of evidence that most errors occur in the preanalytical phase suggest the implementation of a more rigorous methodology for error detection and classification and the adoption of proper technologies for error reduction. Clinical audits should be used as a tool to detect errors caused by organizational problems outside the laboratory.

Molecular diagnostics by microelectronic microchips.

Molecular diagnostics is being revolutionized by the completion of the human genome project and by the development of highly advanced technologies for DNA testing. One of the most important challenges is the introduction of high throughput systems such as DNA chips into diagnostic laboratories. DNA microchips are small devices permitting rapid analysis of genetic information, exploiting miniaturization of all components and automation of operational procedures. The most important biochip applications include gene expression and genetic variation identification and both may improve human molecular diagnostics. Here we review several approaches developed to allow rapid detection of many single nucleotide polymorphisms and mutations in large population samples. Among these, the use of microelectronics seems to best fit with the needs of molecular diagnostics.

A two-center evaluation of the blood gas immediate response mobile analyzer (IRMA).

The Immediate Response Mobile Analyzer (IRMA) is a selective and portable point-of-care testing (POCT) blood gas, electrolyte and hematocrit (Hct) analyzer. The overall analytical performance was evaluated in a two-center study involving two Italian hospital laboratories, following the guidelines suggested by the manufacturer (based on the NCCLS protocol), after a preliminary evaluation of their formal validity. The IRMA was compared to the analyzers used in the routine laboratory as reference. The considered parameters were pH, pO2, pCO2, Na+, K+, ionized calcium and Hct. When using the aqueous quality control material provided by the manufacturer most of the parameters showed good precision, with the exception of pCO2 and pO2 that showed high CVs on two of the three levels of the aqueous control. We could demonstrate that this imprecision was material-related and was reduced when using a different material (blood equilibrated by tonometry). With tonometred blood for pO2 and pCO2 and the aqueous material for the remaining parameters the CVs were all below 5%, ranging from 0.08% to 2.8%. The IRMA results correlated adequately with the comparison instruments, with the exception of sodium and ionized calcium where contradictory results were obtained in the two centers.