Automated parasitological diagnosis in clinical microbiology laboratories.

Although there is a low prevalence of parasitological infections in Europe, the diagnosis of intestinal parasites is still difficult and laborious for microbiology laboratories. Currently, antigen detection assays and molecular biology allow a more accurate diagnosis, but these techniques have limitations as they cannot detect all the possible parasites present in the samples. The objective of the study was to evaluate the accuracy and the usefulness of automated microscopy SediMAX2 (77 Elektronika, Budapest, Hungary) in the detection of parasitic infections from feces. A total of 197 formol-fixed stool samples were processed in parallel by wet mount examination and by SediMAX2. Sensitivities, specificities and predictive values were analyzed, reaching a sensitivity of 89.51% and a specificity of 98.15% and a very good positive predictive value (99.22%). SediMAX2 is a good tool for a reliable diagnosis of intestinal parasitic infections. The rapid processing and the flexibilty of storage of images analyzed make its incorporation into the day to day laboratory routine recommendable.

Validation of a novel and accurate ApoE4 assay for automated chemistry analyzers.

The allele ε4 of the apolipoprotein E gene (APOE ε4) is the major genetic risk factor for non-dominantly inherited Alzheimer's Disease (AD). Current techniques for APOE ε4 carriers identification show good accuracy but have several disadvantages that limit its implementation in a clinical laboratory. These include the need for sample preprocessing, poor automation, low throughput, requirement of additional equipment, and high cost. We followed ISO 13485 guidelines to validate the e4Risk test, a new latex-enhanced immunoturbidimetric blood assay for apolipoprotein E4 (ApoE4) determination in human plasma samples. The test showed high performance in terms of lot to lot variability, precision, interferences, reagents stability, prozone, and detectability. Furthermore, diagnostic accuracy is almost equal (99%) to the gold standard, APOE ε4 genotyping by polymerase chain reaction (PCR). Furthermore, we demonstrated that the e4Risk test can be adapted to any clinical chemistry analyzer, including the high throughput analyzers present in most hospitals and clinical laboratories. The e4Risk test versatility, low cost, and easiness provides an excellent solution for APOE ε4 carriers identification using the same blood sample drawn for biochemical diagnostic work-up of AD patients, which can have important advantages for patient stratification in clinical trials, preventative strategies for AD, and clinical assessment of risk for brain amyloidosis.

Evaluación económica de la implantación del autoanalizador Alfred 60/AST de detección de crecimiento bacteriano con sembrador automático / Economic evaluation of the Alfred 60/AST device implantation for bacterial growth detection with automatic sewing machine

Introducción: En los laboratorios de microbiología se impone cada vez más utilizar sistemas de cribado automatizados para descartar las orinas negativas. Nuestro objetivo fue estimar el umbral presupuestario a partir del cual el autoanalizador Alfred-60/AST sería rentable para nuestro hospital. Material y métodos: Estudio de minimización de costes mediante árboles de decisión, realizado en un Hospital General. Se comparó el coste del urocultivo tradicional con el procesamiento automático mediante Alfred-60/AST. El procesamiento tradicional supone el cultivo manual de todas las orinas recibidas en agar sangre y MacConkey e identificación de todos los microorganismos aislados con el sistema Vitek-2. El autoanalizador sembraría solo las orinas positivas en un medio cromogénico que identificaría directamente los aislamientos de Escherichia coli. Resultados: Las variables con mayor impacto económico en el modelo fueron la probabilidad de obtener un cultivo positivo, la prevalencia de E. coli en los urocultivos y el coste por muestra del sembrador. El análisis de sensibilidad multivariante mostró que el modelo es sólido. El análisis de sensibilidad bivariable mostró que el modelo es sensible a la modificación de los costes, principalmente del sembrador automático. A un valor umbral de 1,40 euros por determinación, el procesamiento automático reduciría los costes anuales en 2.879 euros. Conclusión: La introducción del autoanalizador Alfred-60/AST en nuestro laboratorio a un precio de 1,40 euros por determinación reduciría la carga de trabajo en el procesamiento de orinas, ahorrando tiempo y costes

Introduction: It is becoming increasingly necessary to automatize screening of urine samples to culture at Microbiology laboratories. Our objective was to estimate the budget threshold from which the Alfred 60/AST device would be profitable for our hospital. Material and methods: Cost minimization study by decision trees, carried out in a General Hospital. The cost of traditional urine culture and urine processing using Alfred-60/AST were compared. Traditional processing involves the culture of all urine specimens received onto blood and MacConkey agar, and identification of every microorganism isolated by Vitek-2 system. The autoanalyzer would only inoculate the positive urines onto a chromogenic media, directly identifying the Escherichia coli isolates. Results: The variables with the greatest economic impact in the model were the probability of obtaining a positive culture, the prevalence of E. coli in the urine cultures and the cost per sample using Alfred-60/AST. The multivariate sensitivity analysis showed that the model was solid. The bivariate sensitivity analysis showed that the model is suceptible to cost modification, mainly of the automatic device. At a threshold value of 1.40 euros/determination, the automatic processing would decrease the annual costs in 2,879 euros. Conclusion: The introduction of the Alfred-60/AST device in our laboratory at 1.40 euros/determination would reduce urine processing workload, saving time and costs

Comparison of the performance of the IDEXX SediVue Dx® with manual microscopy for the detection of cells and 2 crystal types in canine and feline urine.

BACKGROUND: Microscopic evaluation of urine is inconsistently performed in veterinary clinics. The IDEXX SediVue Dx® Urine Sediment Analyzer (SediVue) recently was introduced for automated analysis of canine and feline urine and may facilitate performance of urinalyses in practice. OBJECTIVE: Compare the performance of the SediVue with manual microscopy for detecting clinically relevant numbers of cells and 2 crystal types. SAMPLES: Five-hundred thirty urine samples (82% canine, 18% feline). METHODS: For SediVue analysis (software versions [SW] 1.0.0.0 and 1.0.1.3), uncentrifuged urine was pipetted into a cartridge. Images were captured and processed using a convolutional neural network algorithm. For manual microscopy, urine was centrifuged to obtain sediment. To determine sensitivity and specificity of the SediVue compared with manual microscopy, thresholds were set at ≥5/high power field (hpf) for red blood cells (RBC) and white blood cells (WBC) and ≥1/hpf for squamous epithelial cells (sqEPI), non-squamous epithelial cells (nsEPI), struvite crystals (STR), and calcium oxalate dihydrate crystals (CaOx Di). RESULTS: The sensitivity of the SediVue (SW1.0.1.3) was 85%-90% for the detection of RBC, WBC, and STR; 75% for CaOx Di; 71% for nsEPI; and 33% for sqEPI. Specificity was 99% for sqEPI and CaOx Di; 87%-90% for RBC, WBC, and nsEPI; and 84% for STR. Compared to SW1.0.0.0, SW1.0.1.3 had increased sensitivity but decreased specificity. Performance was similar for canine versus feline and fresh versus stored urine samples. CONCLUSIONS AND CLINICAL IMPORTANCE: The SediVue exhibits good agreement with manual microscopy for the detection of most formed elements evaluated, but improvement is needed for epithelial cells.

A two-step homogeneous assay for apolipoprotein E-containing high-density lipoprotein-cholesterol.

BACKGROUND: Apolipoprotein E-containing high-density lipoprotein shows antiatherogenic properties in vitro. There is a need for a homogeneous assay to determine the concentration of apolipoprotein E-containing high-density lipoprotein for in vivo studies. METHODS: In the proposed homogeneous assay, lipoproteins other than apolipoprotein E-containing high-density lipoprotein were eliminated in the first step. Apolipoprotein E-containing high-density lipoprotein-cholesterol was measured in the second step. The control study used a 13% polyethylene glycol precipitation assay (control assay). RESULTS: The homogeneous assay showed good performance in validation studies. In subjects with normal liver function ( n = 78), a significant correlation was found between the control assay and the homogeneous assay ( r = 0.824). Serum apolipoprotein E-containing high-density lipoprotein cholesterol concentrations, determined by the control assay and the homogeneous assay, respectively, were 0.05 (0.04-0.10) (median [25th-75th percentile]) mmol/L and 0.10 (0.06-0.13) mmol/L for healthy individuals ( n = 12), and 0.03 (0.01-0.13) mmol/L and 0.02 (0.01-0.02) mmol/L for patients with cholestasis ( n = 6). The results indicate that the homogeneous assay recovers cholesterol contained in physiological apolipoprotein E-containing high-density lipoprotein, but not in pathological apolipoprotein E-containing high-density lipoprotein from cholestatic patients. CONCLUSIONS: The proposed two-step homogeneous assay enables selective measurement of physiological apolipoprotein E-containing high-density lipoprotein cholesterol in common autoanalysers. This assay might uncover a role for apolipoprotein E-containing high-density lipoprotein in physiological conditions.

Comparison of Enterprise Point-of-Care and Nova Biomedical Critical Care Xpress analyzers for determination of arterial pH, blood gas, and electrolyte values in canine and equine blood.

BACKGROUND: Point-of-care analyzers can provide a rapid turnaround time for critical blood test results. Agreement between the Enterprise Point-of-Care (EPOC) and bench-top laboratory analyzers is important to determine the clinical reliability of the EPOC. OBJECTIVES: The aim of the study was (1) to evaluate the precision (repeatability) of blood gas values measured by the EPOC and (2) to determine the level of agreement between the EPOC and Nova Critical Care Express (Nova CCX) for the assessment of arterial pH, blood gases, and electrolyte variables in canine and equine blood. METHODS: Arterial blood samples from dogs were analyzed on the EPOC and Nova CCX analyzers to determine precision and agreement of pH, PaCO2 , PaO2 , and HCT. The same analytes plus Na+ , K- , and Cl- were analyzed for agreement using equine blood. Statistical analyses included assessment of precision using the coefficient of variation (CV%), and agreement using the Deming regression, Pearson correlation, and Bland-Altman plots. RESULTS: Both analyzers provided precise results of pH, PaCO2 , PaO2, and HCT, meeting CV% quality requirement values. In both species, Deming regression results were acceptable and correlation values were above 0.93 for arterial pH and blood gases, but lower for sodium and chloride. Bland-Altman plots demonstrated varying degrees of bias, but good agreement between the 2 analyzers was seen when arterial blood gases and electrolytes were measured, except for PaCO2 and Cl-. CONCLUSION: The EPOC analyzer provides consistent, reliable results for canine arterial blood gas values and for equine arterial blood gas and electrolyte values. Cl- results could be acceptable with the application of a correction factor, but the PaCO2 results were more variable.

Evaluation of the GeneXpert MTB/RIF in patients with presumptive tuberculous meningitis.

BACKGROUND: Meningitis caused by Mycobacterium tuberculosis is a major cause of morbidity and mortality worldwide. We evaluated the performance of cerebrospinal fluid (CSF) testing with the GeneXpert MTB/RIF assay versus traditional approaches for diagnosing tuberculosis meningitis (TBM). METHODS: Patients were adults (n = 37) presenting with suspected TBM to the Hospital Nacional Dos de Mayo, Lima, Peru, during 12 months until 1st January 2015. Each participant had a single CSF specimen that was divided into aliquots that were concurrently tested for M. tuberculosis using GeneXpert, Ziehl-Neelsen smear and culture on solid and liquid media. Drug susceptibility testing used Mycobacteria Growth Indicator Tube (MGIT 960) and the proportions method. RESULTS: 81% (30/37) of patients received a final clinical diagnosis of TBM, of whom 63% (19/30, 95% confidence intervals, CI: 44-80%) were HIV-positive. 22% (8/37, 95%CI: 9.8-38%), of patients had definite TBM. Because definite TBM was defined by positivity in any laboratory test, all laboratory tests had 100% specificity. Considering the 30 patients who had a clinical diagnosis of TBM: diagnostic sensitivity was 23% (7/30, 95%CI: 9.9-42%) for GeneXpert and was the same for all culture results combined; considerably greater than 7% (2/30, 95%CI: 0.82-22%) for microscopy; whereas all laboratory tests had poor negative predictive values (20-23%). Considering only the 8 patients with definite TBM: diagnostic sensitivity was 88% (7/8, 95%CI: 47-100%) for GeneXpert; 75% (6/8, 95%CI: 35-97%) for MGIT culture or LJ culture; 50% (4/8, 95%CI 16-84) for Ogawa culture and 25% (2/8, 95%CI: 3.2-65%) for microscopy. GeneXpert and microscopy provided same-day results, whereas culture took 20-56 days. GeneXpert provided same-day rifampicin-susceptibility results, whereas culture-based testing took 32-71 days. 38% (3/8, 95%CI: 8.5-76%) of patients with definite TBM with data had evidence of drug-resistant TB, but 73% (22/30) of all clinically diagnosed TBM (definite, probable, and possible TBM) had no drug-susceptibility results available. CONCLUSIONS: Compared with traditional culture-based methods of CSF testing, GeneXpert had similar yield and faster results for both the detection of M. tuberculosis and drug-susceptibility testing. Including use of the GeneXpert has the capacity to improve the diagnosis of TBM cases.

AutoSeqMan: batch assembly of contigs for Sanger sequences.

With the wide application of DNA sequencing technology, DNA sequences are still increasingly generated through the Sanger sequencing platform. SeqMan (in the LaserGene package) is an excellent program with an easy-to-use graphical user interface (GUI) employed to assemble Sanger sequences into contigs. However, with increasing data size, larger sample sets and more sequenced loci make contig assemble complicated due to the considerable number of manual operations required to run SeqMan. Here, we present the 'autoSeqMan' software program, which can automatedly assemble contigs using SeqMan scripting language. There are two main modules available, namely, 'Classification' and 'Assembly'. Classification first undertakes preprocessing work, whereas Assembly generates a SeqMan script to consecutively assemble contigs for the classified files. Through comparison with manual operation, we showed that autoSeqMan saved substantial time in the preprocessing and assembly of Sanger sequences. We hope this tool will be useful for those with large sample sets to analyze, but with little programming experience. It is freely available at https://github.com/ Sun-Yanbo/autoSeqMan.

Factores asociados a la adherencia al autoanálisis de la glucemia capilar en personas con diabetes en tratamiento con insulina. Estudio dapa / Factors associated to adherence to blood glucose self-monitoring in patients with diabetes treated with insulin. The dapa study

Objetivo: El objetivo principal del estudio fue determinar la adherencia al autoanálisis de la glucemia capilar y los principales factores que influyen en ella, con especial atención a los relacionados con la percepción glucémica, en personas con diabetes tipo 1 o 2 en tratamiento con insulina. Material y métodos: Estudio epidemiológico, observacional, prospectivo y multicéntrico realizado en condiciones de práctica clínica habitual en centros de Atención Primaria, ambulatorios y hospitalarios de distintas comunidades autónomas. Se recogieron datos sociodemográficos, clínicos y de tratamiento. Las personas fueron consideradas adherentes si realizaban el número mínimo de controles recomendado por la Sociedad Española de Diabetes. Resultados: El 61,6% de los pacientes demostraron ser adherentes. Los factores asociados a la adherencia fueron tratamiento con insulina de menos de 3 inyecciones diarias (OR: 2,678; IC 95%: 2,048-3,5029; p<0,001), presentar enfermedad vascular periférica (OR: 1,529; IC 95%: 1,077-2,171; p=0,018), no tomar alcohol (OR: 1,442; IC 95%: 1,118-1,858; p=0,005) y recoger las tiras reactivas en la farmacia (OR: 1,275; IC 95%: 1,026-1,584; p=0,028). El 21,4% de los pacientes presentaron una autopercepción glucémica correcta. Conclusiones: Los resultados encontrados demuestran una adherencia al autoanálisis subóptima con respecto a las recomendaciones establecidas por la Sociedad Española de Diabetes en las personas con diabetes en tratamiento con insulina. Las variables independientes asociadas con una buena adherencia fueron tratamiento con menos de 3 inyecciones de insulina al día, presentar enfermedad vascular periférica, no tomar alcohol y retirar las tiras reactivas en la farmacia (AU)

Objective: To assess adherence to self-monitoring of blood glucose and the main factors associated with it, particularly those related to self-perception of glycemia, in patients with diabetes on insulin therapy. Patients and methods: An epidemiological, observational, prospective, multicenter study conducted in standard clinical practice in primary care, outpatient centers, and hospitals from different Spanish regions. Sociodemographic, clinical and treatment data were collected. Patients were considered adherent to self-monitoring if they performed the minimum number of controls recommended by the Spanish Society of Diabetes (SED). Results: Adherence was shown in 61.6% of patients. Factors associated to adherence included treatment with less than three insulin injections daily (OR 2.678; 95% CI 2.048- 3.5029; p <0.001), presence of peripheral vascular disease (OR 1.529; 95% CI 1.077 - 2.171; p=0.018), alcohol abstinence (OR 1.442; 95% CI 1.118 - 1.858; p=0.005), and collection of the glucose test strips from the pharmacy (OR 1.275; 95% CI 1.026 - 1.584; p=0.028). Adequate self-perception of glycemia was found in 21.4% of patients. Conclusions Our results show a suboptimal adherence to the recommended protocol for blood glucose self-monitoring in patients with diabetes on insulin therapy. Independent variables associated to good adherence were treatment with less than three insulin injections dailyu, presence of peripheral vascular disease, alcohol abstinence, and collection of glucose test strips from the pharmacy (AU)

Detection of ingested nitromethane and reliable creatinine assessment using multiple common analytical methods.

AIM: Nitromethane, found in fuels used for short distance racing, model cars, and model airplanes, produces a falsely elevated serum creatinine with standard creatinine analysis via the Jaffé method. Erroneous creatinine elevation often triggers extensive testing, leads to inaccurate diagnoses, and delayed or inappropriate medical interventions. Multiple reports in the literature identify "enzymatic assays" as an alternative method to detect the true value of creatinine, but this ambiguity does not help providers translate what type of enzymatic assay testing can be done in real time to determine if there is indeed false elevation. METHODS: We report seven cases of ingested nitromethane where creatinine was determined via Beckman Coulter® analyser using the Jaffé method, Vitros® analyser, or i-Stat® point-of-care testing. Nitromethane was detected and semi-quantified using a common clinical toxic alcohol analysis method, and quantified by headspace-gas chromatography-mass spectrometry. RESULTS: When creatinine was determined using i-Stat® point-of-care testing or a Vitros® analyser, levels were within the normal range. Comparatively, all initial creatinine levels obtained via the Jaffé method were elevated. Nitromethane concentrations ranged from 42 to 310 µg/mL. CONCLUSIONS: These cases demonstrate reliable assessment of creatinine through other enzymatic methods using a Vitros® analyser or i-STAT®. Additionally, nitromethane is detectable and quantifiable using routine alcohols gas chromatography analysis and by headspace-gas chromatography-mass spectrometry.

Rapid detection of Group B streptococcus directly from vaginal-rectal specimens using liquid swabs and the BD Max GBS assay.

OBJECTIVE: We adapted the BD Max GBS assay, an automated platform for the detection of Group B streptococcus (GBS) DNA in vaginal-rectal swab specimens after LIM broth enrichment, to directly detect GBS in specimens collected using cellular foam swabs in Amies liquid medium. We compared the BD Max GBS assay performance to that of enriched culture and the BD GeneOhm StrepB assay. METHODS: Seventy-two reference vaginal-rectal specimens were employed to determine the limit of GBS detection and the preferred test volume for direct detection of GBS. A total of 304 clinical specimens were then tested by the optimized BD Max GBS assay, both by direct testing and following broth enrichment. RESULTS: The limit of GBS detection was 75 CFU/mL and the preferred test volume was 100 µL. Of 304 clinical specimens tested, GBS was detected in 62 specimens by enriched culture (20.4%); 61 of these yielded GBS by the BD Max GBS assay when performed directly from the liquid swab (sensitivity 98.4%). All 242 culture-negative specimens also yielded negative results by the BD Max GBS assay (specificity 100%). When this assay was performed following broth enrichment, GBS was detected in all 62 culture-positive specimens (100% sensitivity). The sensitivity and specificity of the BD GeneOhm StrepB assay was 90.3% and 99%, respectively. CONCLUSIONS: The BD Max GBS assay is highly sensitive, requires minimal technical skill with <2 min required to set-up, and results are available in under 80 min (versus 24-48 h for culture). It is configured for 'on demand' testing and vaginal-rectal specimens can be rapidly screened for GBS without the need for enrichment. The results obtained in this study demonstrate that rapid GBS screening using the BD Max GBS assay at the time of delivery is a viable alternative to the current recommended screening at 35-37 weeks of gestation with pre-enrichment testing methods.

Exactitud y concordancia entre glucómetros: un estudio en condiciones habituales de práctica clínica / Accuracy and reliability between glucose meters: a study under normal clinical practice conditions

Introducción. Los glucómetros demuestran habitualmente una gran exactitud, y en la práctica, la glucemia capilar y la glucemia plasmática (GP) son utilizadas indistintamente. Sin embargo, numerosas variables pueden afectar la validez de estos aparatos. El objetivo de este estudio fue conocer la exactitud y la concordancia de 3 glucómetros utilizados en las consultas de un EAP. Material y métodos. De 59 participantes se obtuvieron una muestra de sangre venosa y una gota de sangre capilar, que fue analizada en 3 glucómetros: 2 FreeStyle® Optium (OP1 y OP2) y un Accu-Chek® Aviva. El valor de referencia fue la GP y fueron analizados asimismo el hematocrito y los niveles plasmáticos de urea, bilirrubina, ácido úrico y triglicéridos. Se utilizaron la regresión de Passing-Bablok para la exactitud, y el coeficiente de correlación intraclase y el método Bland-Altman para la concordancia. Se ha considerado el estándar actual (American Diabetes Association) de un error tolerado de±5%. Resultados. La diferencia de medias±desviación estándar (mg/dL) y el error sistemático fueron: 5,8±7 y 5,8% (OP1); 6,2±8 y 5,9% (OP2); 8,3±8 y 6,3% (Accu-Chek®). El par más concordante fue OP1/OP2, con un coeficiente de correlación intraclase=0,97, sesgo=−0,4mg/dL y una amplitud de los límites de acuerdo con el 95%=28,6mg/dL. Se observaron los mayores grados de exactitud y de concordancia en rangos glucémicos elevados (GP≥126mg/dL). Conclusiones. Aunque mostraron una diferencia de medias clínicamente aceptable respecto a la GP, los 3 glucómetros incumplieron el estándar actual de la American Diabetes Association. Es recomendable la realización periódica de controles de calidad de estos dispositivos (AU)

Introduction. The glucose meters usually show a high accuracy, and in clinical practice, capillary and plasma glucose (PG) are used interchangeably. However, many variables can affect the validity of these devices. The aim of this study was to determine the accuracy and reliability of 3 glucose meters that are currently used in a primary care centre. Material and methods. A sample of venous blood and a drop of capillary blood were obtained from 59 participants. The drop was analysed in 3 glucose meters: 2 FreeStyle® Optium (OP1 and OP2), and one Accu-Chek® Aviva. The PG acted as the reference value, and the haematocrit and plasma levels of urea, bilirubin, uric acid and triglycerides were also analysed. We used the Passing-Bablok regression for accuracy and the intraclass correlation coefficient and the Bland-Altman method for reliability. The current American Diabetes Association standard of a total error of±5% was applied. Results. Differences in mean±standard deviation (mg/dL) and the systematic error were 5.8±7 and 5.8% (OP1); 6.2±8 and 5.9% (OP2); 8.3±8 and 6.3% (Accu-Chek®). The OP1/OP2 pair showed the highest level of reliability, with an intraclass correlation coefficient=0.97, bias=−0.4mg/dL, and a width of the 95% limits of agreement of 28.6mg/dL. The highest levels of accuracy and reliability were observed in high glucose ranges (PG≥126mg/dL). Conclusions. Despite their clinically acceptable mean difference compared to the PG, the 3 glucose meters did not fulfill the current American Diabetes Association standard. The regular performance of quality control tests of these devices is recommended (AU)

Development and Evaluation of a Blood Culture PCR Assay for Rapid Detection of Salmonella Paratyphi A in Clinical Samples.

BACKGROUND: Enteric fever remains an important cause of morbidity in many low-income countries and Salmonella Paratyphi A has emerged as the aetiological agent in an increasing proportion of cases. Lack of adequate diagnostics hinders early diagnosis and prompt treatment of both typhoid and paratyphoid but development of assays to identify paratyphoid has been particularly neglected. Here we describe the development of a rapid and sensitive blood culture PCR method for detection of Salmonella Paratyphi A from blood, potentially allowing for appropriate diagnosis and antimicrobial treatment to be initiated on the same day. METHODS: Venous blood samples from volunteers experimentally challenged orally with Salmonella Paratyphi A, who subsequently developed paratyphoid, were taken on the day of diagnosis; 10 ml for quantitative blood culture and automated blood culture, and 5 ml for blood culture PCR. In the latter assay, bacteria were grown in tryptone soy broth containing 2.4% ox bile and micrococcal nuclease for 5 hours (37°C) before bacterial DNA was isolated for PCR detection targeting the fliC-a gene of Salmonella Paratyphi A. RESULTS: An optimized broth containing 2.4% ox bile and micrococcal nuclease, as well as a PCR test was developed for a blood culture PCR assay of Salmonella Paratyphi A. The volunteers diagnosed with paratyphoid had a median bacterial burden of 1 (range 0.1-6.9) CFU/ml blood. All the blood culture PCR positive cases where a positive bacterial growth was shown by quantitative blood culture had a bacterial burden of ≥ 0.3 CFU/ ml blood. The blood culture PCR assay identified an equal number of positive cases as automated blood culture at higher bacterial loads (≥0.3 CFU/ml blood), but utilized only half the volume of specimens. CONCLUSIONS: The blood culture PCR method for detection of Salmonella Paratyphi A can be completed within 9 hours and offers the potential for same-day diagnosis of enteric fever. Using 5 ml blood, it exhibited a lower limit of detection equal to 0.3 CFU/ml blood, and it performed at least as well as automated blood culture at higher bacterial loads (≥0.3 CFU/ml blood) of clinical specimens despite using half the volume of blood. The findings warrant its further study in endemic populations with a potential use as a novel diagnostic which fills the present gap of paratyphoid diagnostics.

Psychometric evaluation of the Self-Appraisal Questionnaire in a Spanish sample of offenders / Evaluación psicométrica del Cuestionario de Auto-valoración en una muestra española de delincuentes

BACKGROUND: The Self-Appraisal Questionnaire (SAQ) is a self-report instrument designed to predict recidivism among adult criminal offenders. The aim of this study was to evaluate the psychometric properties of this self-report in a Spanish sample of offenders. METHOD: The questionnaire was administered to 276 offenders recruited from various prisons in Madrid (Spain). RESULTS: Confirmatory factor analyses showed that the underlying structure of SAQ was best explained by a one-factor solution. SAQ total scores exhibited high levels of internal consistency (.92). Correlations of the instrument with violence risk measures were statistically significant and had a moderate magnitude, indicating a reasonable degree of concurrent validity. CONCLUSIONS: After examination of its psychometric properties, it was concluded that the SAQ total score is a reliable and valid measure to estimate violence risk in Spanish offenders

ANTECEDENTES: el Cuestionario de Auto-Valoración (SAQ) es un instrumento de auto-informe diseñado para predecir el riesgo de reincidencia en población penitenciaria. El objetivo de este estudio fue evaluar sus propiedades psicométricas en una muestra española de delincuentes. MÉTODO: el cuestionario fue administrado a 276 delincuentes procedentes de varias prisiones de Madrid (España). RESULTADOS: el análisis factorial confirmatorio mostró que la estructura subyacente del SAQ fue explicada por una solución uni-factorial. El coeficiente alfa de Cronbach obtenido para la puntuación total del SAQ fue alto (.92). Las correlaciones obtenidas con otras medidas del riesgo de violencia fueron estadísticamente significativas y tuvieron una magnitud moderada, indicando un razonable grado de validez concurrente del instrumento. CONCLUSIONES: después de examinar sus propiedades psicométricas, la puntuación total del SAQ proporciona una medida suficientemente fiable y válida para estimar el riesgo de violencia en población de delincuentes españoles

A Novel ImageJ Macro for Automated Cell Death Quantitation in the Retina.

PURPOSE: TUNEL assay is widely used to evaluate cell death. Quantification of TUNEL-positive (TUNEL+) cells in tissue sections is usually performed manually, ideally by two masked observers. This process is time consuming, prone to measurement errors, and not entirely reproducible. In this paper, we describe an automated quantification approach to address these difficulties. METHODS: We developed an ImageJ macro to quantitate cell death by TUNEL assay in retinal cross-section images. The script was coded using IJ1 programming language. To validate this tool, we selected a dataset of TUNEL assay digital images, calculated layer area and cell count manually (done by two observers), and compared measurements between observers and macro results. RESULTS: The automated macro segmented outer nuclear layer (ONL) and inner nuclear layer (INL) successfully. Automated TUNEL+ cell counts were in-between counts of inexperienced and experienced observers. The intraobserver coefficient of variation (COV) ranged from 13.09% to 25.20%. The COV between both observers was 51.11 ± 25.83% for the ONL and 56.07 ± 24.03% for the INL. Comparing observers' results with macro results, COV was 23.37 ± 15.97% for the ONL and 23.44 ± 18.56% for the INL. CONCLUSIONS: We developed and validated an ImageJ macro that can be used as an accurate and precise quantitative tool for retina researchers to achieve repeatable, unbiased, fast, and accurate cell death quantitation. We believe that this standardized measurement tool could be advantageous to compare results across different research groups, as it is freely available as open source.

Automated urine screening devices make urine sediment microscopy in diagnostic laboratories economically viable.

Automated urinalysis devices are reproducible, accurate and faster than the standard manual microscopy. Economic analysis has shown that decreases in turn-around-time and labour cost savings offered by these devices make them more economic than manual microscopy.

Detecting endotoxin activity in bovine serum using an automated testing system.

The aim of the present study was to compare the ability of the commercially available portable test system (PTS(TM)) to detect endotoxin activity in bovine serum, with that of the traditional LAL-kinetic turbidimetric (KT) and chromogenic (KC) assays. Prior to testing, serum samples, which were obtained from endotoxin-challenged cattle, were diluted 1:20 in endotoxin-free water and heated to 80°C for 10 min. The performance of the PTS(TM) was not significantly different from that of the traditional LAL-based assays. The results using PTS(TM) correlated with those using KT (r(2)=0.963, P<0.001) or KC assays (r(2)=0.982, P<0.001). Based on these findings, the PTS(TM) could be applied as a simplified system to assess endotoxin activity in bovine serum.

Clinical application evaluation of two fourth-generation human immunodeficiency virus (HIV) screening assays in West China Hospital.

BACKGROUND: Fourth-generation human immunodeficiency virus (HIV) screening assays have been used in many laboratories. The Elecsys® HIV combi PT assay is a new kind of fourth-generation HIV screening assay developed to allow earlier detection of seroconversion. METHODS: A total of 271,845 routine specimens were detected using the Elecsys® HIV combi assay and Elecsys® HIV combi PT assay from September 2010 to December 2012 in a large university hospital. Repeatedly, reactive screening samples were confirmed according to recommended confirmatory algorithms. RESULTS: The false-positive rate and positive predictive value (PPV) of two assays are 0.08 and 78.35%, respectively, for the Elecsys® HIV combi assay and 0.07 and 82.21% for the Elecsys® HIV combi PT assay. Ninety-four percent cases with cutoff index ratio <15.0 were false-positive. When we set the specificity as 95.0 and 99.0%, PPV could increase to 98.7, 99.6, 98.8, and 99.7%, and sensitivity reduced to 99.2, 98.4, 98.5, and 96.8% for the Elecsys® HIV combi assay and the Elecsys® HIV combi PT assay, respectively. CONCLUSIONS: The Elecsys® HIV combi PT assay shows a better performance in specificity than the Elecsys® HIV combi assay. Most weakly reactive results were false-positive, this means it still need to be improved and it will need laboratory personnel to communicate with the clinical doctor and patients more properly about the result of the assay.