Reference Laboratory For Testing Research Articles

A semiautomated microfluidic ELISA for the detection of hemophagocytic lymphohistiocytosis biomarkers.

Hemophagocytic lymphohistiocytosis (HLH) is a rare, life-threatening condition characterized by a massive overactivation of the immune system. Because the clinical findings are nonspecific, the development of assays to facilitate rapid diagnosis is critical for patient care. The objectives of this study were to evaluate the performance of a microfluidic enzyme-linked immunosorbent assay (ELISA) for HLH biomarkers and investigate the impact of insourcing this testing on workflow, cost, and turnaround time in a tertiary-care cancer hospital. Trends in order volume were evaluated for C-X-C motif chemokine ligand 9 (CXCL9) and soluble interleukin 2 receptor ɑ (sIL2R), and a microfluidic ELISA was used to measure these analytes in serum samples. Analyte values, turnaround time, and costs were compared for this assay relative to reference laboratory testing. Test ordering has increased from 187 to 1030 requests annually over the past 5 years. Insourcing these analytes on a semiautomated ELISA can decrease time to result by approximately 2 days and generate a cost savings of roughly $140,000 annually within our laboratory. Using a semiautomated ELISA for sIL2R and CXCL9 may help physicians arrive at a diagnosis and monitor therapy for patients with HLH while decreasing turnaround time and costs within the clinical laboratory.

Specificity of serological screening tests and reference laboratory tests to diagnose gambiense human African trypanosomiasis: a prospective clinical performance study

BackgroundSerological screening tests play a crucial role to diagnose gambiense human African trypanosomiasis (gHAT). Presently, they preselect individuals for microscopic confirmation, but in future “screen and treat” strategies they will identify individuals for treatment. Variability in reported specificities, the development of new rapid diagnostic tests (RDT) and the hypothesis that malaria infection may decrease RDT specificity led us to evaluate the specificity of 5 gHAT screening tests.MethodsDuring active screening, venous blood samples from 1095 individuals from Côte d’Ivoire and Guinea were tested consecutively with commercial (CATT, HAT Sero-K-SeT, Abbott Bioline HAT 2.0) and prototype (DCN HAT RDT, HAT Sero-K-SeT 2.0) gHAT screening tests and with a malaria RDT. Individuals with ≥ 1 positive gHAT screening test underwent microscopy and further immunological (trypanolysis with T.b. gambiense LiTat 1.3, 1.5 and 1.6; indirect ELISA/T.b. gambiense; T.b. gambiense inhibition ELISA with T.b. gambiense LiTat 1.3 and 1.5 VSG) and molecular reference laboratory tests (PCR TBRN3, 18S and TgsGP; SHERLOCK 18S Tids, 7SL Zoon, and TgsGP; Trypanozoon S2-RT-qPCR 18S2, 177T, GPI-PLC and TgsGP in multiplex; RT-qPCR DT8, DT9 and TgsGP in multiplex). Microscopic trypanosome detection confirmed gHAT, while other individuals were considered gHAT free. Differences in fractions between groups were assessed by Chi square and differences in specificity between 2 tests on the same individuals by McNemar.ResultsOne gHAT case was diagnosed. Overall test specificities (n = 1094) were: CATT 98.9% (95% CI: 98.1–99.4%); HAT Sero-K-SeT 86.7% (95% CI: 84.5–88.5%); Bioline HAT 2.0 82.1% (95% CI: 79.7–84.2%); DCN HAT RDT 78.2% (95% CI: 75.7–80.6%); and HAT Sero-K-SeT 2.0 78.4% (95% CI: 75.9–80.8%). In malaria positives, gHAT screening tests appeared less specific, but the difference was significant only in Guinea for Abbott Bioline HAT 2.0 (P = 0.03) and HAT Sero-K-Set 2.0 (P = 0.0006). The specificities of immunological and molecular laboratory tests in gHAT seropositives were 98.7–100% (n = 399) and 93.0–100% (n = 302), respectively. Among 44 reference laboratory test positives, only the confirmed gHAT patient and one screening test seropositive combined immunological and molecular reference laboratory test positivity.ConclusionsAlthough a minor effect of malaria cannot be excluded, gHAT RDT specificities are far below the 95% minimal specificity stipulated by the WHO target product profile for a simple diagnostic tool to identify individuals eligible for treatment. Unless specificity is improved, an RDT-based “screen and treat” strategy would result in massive overtreatment. In view of their inconsistent results, additional comparative evaluations of the diagnostic performance of reference laboratory tests are indicated for better identifying, among screening test positives, those at increased suspicion for gHAT.Trial registrationThe trial was retrospectively registered under NCT05466630 in clinicaltrials.gov on July 15 2022.Graphical

How anti-c in a D- patient prompted lifesaving work between a transfusion service and a blood center reference laboratory.

This case report showcases an extraordinary collaboration to support the transfusion needs of a patient with a rare phenotype and long-standing anemia due to gastrointestinal bleeding. This report describes the Immunohematology Reference Laboratory testing and logistics of rare blood provision over an 11-year period, as well as a summary of the hematologic, gastroenterologic, and surgical interventions. This case illustrates how a strong collaboration among the clinical team, laboratory, blood center, and the rare donor community facilitated successful management of this patient's anemia until the patient could receive life-changing treatment.

Initially categorized 46,XY embryo transfer ending with 45,X products of conception—a case report and a review of discordant result management

ObjectiveTo report a case of an initially categorized euploid, male embryo screened by preimplantation genetic testing (PGT) resulting in miscarriage and testing of products of conception consistent with Turner syndrome, and to discuss additional workup and considerations in cases of discrepancy. DesignCase report. SettingUniversity fertility clinic. Patient(s)A couple seeking procreative management for female partner having a balanced translocation 46,XX,t(14;16)(q21;q21) diagnosed after couple’s previous child passed due to segmental duplication in chromosomes 14 and 16 and pursued in vitro fertilization (IVF) for PGT for structural rearrangements (PGT-SR). Main Outcome Measure(s)Miscarriage with discordant chromosomal microarray (CMA) result Result(s)Couple conceived with transfer of a euploid male embryo. After initial confirmation of pregnancy, repeat imaging indicated a missed abortion. Dilation and curettage was performed and products of conception were sent for CMA.Results Indicated Turner syndrome (45,X). Follow up short tandem repeat (STR) analysis confirmed the products of conception were from the tested embryo. After reevaluation of data, copy number variations below the reporting threshold for the sex chromosomes, were observable and compatible with mosaic 45,X/46,XY. Conclusion(s)The limitations of PGT should be kept in mind when counseling patients due to both the sample provided by biopsy, sequencing platforms, and laboratory pipeline for diagnosis. We recommend that patients be counseled about these limitations and offered antenatal and postnatal testing as indicated. When discrepancies are seen after PGT, collaboration with the reference laboratory and additional testing with STR analysis should be considered when possible.

A Critical Review of Methods for Backfill Soil Modulus in Design of Flexible Culverts

Flexible culverts made of corrugated steel or plastic are cost-effective and environmentally friendly alternatives to conventional small road and railway bridges. These structures interact with the backfill by deflecting when subjected to overburden loads, enabling them to utilize the surrounding soil by carrying loads in ring compression. In low soil cover situations, the relationship between bending and backfill soil (stiffness) modulus increasingly influences bearing capacity, and therefore must be considered in design. Backfill soil modulus is a direct result of the execution of the backfilling, and recognized as the most important design parameter because of local uncertainties during construction and material variability. This paper gives a review of some of the existing methods for determining backfill soil modulus. It covers development history, theoretical approximations, aspects of crushed rock materials and their quality, and ease of use in routine design. By applying the methods on different materials and comparing the end results with a compilation of large-scale compression tests and materials from various origins, the performance of the reviewed methods is evaluated. It is found that the reviewed methods have specific drawbacks depending on the actual stress condition and backfill material being applied. In addition, most methods are based on reference laboratory tests carried out on specific and sometimes high-quality materials, and therefore fail to reflect how the quality of rock materials influences the backfill modulus. These shortcomings are used to suggest a new outlook that should be considered in future research on backfill design.

An Evaluation of the Performance, Patient Acceptability, and Feasibility of a Point-of-Care HIV-Syphilis Assay in an Urban Emergency Department.

Point-of-care (POC) tests for sexually transmitted infections (STIs) permit delivery of results during the patient's emergency department (ED) encounter. We evaluated performance, patient acceptability, and feasibility of a new duplex POC test, Chembio Dual Path Platform HIV-Syphilis Assay, in an urban ED setting. Convenience sampling approach prioritizing those considered at increased risk for an STI and/or with a history of HIV. For the performance evaluation, participants were tested for HIV/syphilis with the Chembio POC assay and the reference laboratory tests; sensitivity and specificity were determined. For the patient acceptability evaluation, participants completed pre- and post-user surveys. For the feasibility evaluation, ED clinical technicians completed a survey evaluating their perceptions regarding feasibility of use of this POC test. A total of 327 patients were consented and enrolled. The diagnostic sensitivity and specificity of the Chembio POC assay for HIV were 96.5% (95% confidence interval [CI], 90.1%-99.3%) and 99.6% (95% CI, 97.7%-100.0%), respectively, and for syphilis, the values were 93.9% (95% CI, 85.0%-98.3%) and 99.6% (95% CI, 97.9%-100.0%), respectively. Regarding patient acceptability, 87% trusted the result, and 93% reported that they were more likely to seek treatment if they received a positive STI test result in the ED rather than after the ED visit. Regarding feasibility, 90% of the technicians reported that they would recommend using the test in EDs. The Chembio Dual Path Platform HIV-Syphilis POC Assay had excellent performance characteristics when evaluated in an ED population, as well as high perceived acceptability from patients, and feasibility for ED use from clinical technicians. The test may have utility for HIV-syphilis screening among high-risk ED patients.

Re-testing as a method of implementing external quality assessment program for COVID-19 real time PCR testing in Uganda.

Significant milestones have been made in the development of COVID19 diagnostics Technologies. Government of the republic of Uganda and the line Ministry of Health mandated Uganda Virus Research Institute to ensure quality of COVID19 diagnostics. Re-testing was one of the methods initiated by the UVRI to implement External Quality assessment of COVID19 molecular diagnostics. participating laboratories were required by UVRI to submit their already tested and archived nasopharyngeal samples and corresponding meta data. These were then re-tested at UVRI using the WHO Berlin protocol, the UVRI results were compared to those of the primary testing laboratories in order to ascertain performance agreement for the qualitative & quantitative results obtained. Ms Excel window 12 and GraphPad prism ver 15 was used in the analysis. Bar graphs, pie charts and line graphs were used to compare performance agreement between the reference Laboratory and primary testing Laboratories. Eleven (11) Ministry of Health/Uganda Virus Research Institute COVID19 accredited laboratories participated in the re-testing of quality control samples. 5/11 (45%) of the primary testing laboratories had 100% performance agreement with that of the National Reference Laboratory for the final test result. Even where there was concordance in the final test outcome (negative or positive) between UVRI and primary testing laboratories, there were still differences in CT values. The differences in the Cycle Threshold (CT) values were insignificant except for Tenna & Pharma Laboratory and the UVRI(p = 0.0296). The difference in the CT values were not skewed to either the National reference Laboratory(UVRI) or the primary testing laboratory but varied from one laboratory to another. In the remaining 6/11 (55%) laboratories where there were discrepancies in the aggregate test results, only samples initially tested and reported as positive by the primary laboratories were tested and found to be false positives by the UVRI COVID19 National Reference Laboratory. False positives were detected from public, private not for profit and private testing laboratories in almost equal proportion. There is need for standardization of molecular testing platforms in Uganda. There is also urgent need to improve on the Laboratory quality management systems of the molecular testing laboratories in order to minimize such discrepancies.

Assessing the Impact of Melanin Content on the Reliability of the Idylla™ BRAF Mutation Test

Aims: This study aims to investigate the potential influence of melanin content on the performance of the Idylla™ BRAF Mutation Test. Specifically, we assess whether melanin levels in samples impact the test’s reliability, thereby validating its clinical utility in accelerating melanoma diagnosis and potentially improving patient prognosis. Methods: We conducted a retrospective analysis of 98 confirmed melanoma samples collected between February 2020 and November 2020. Formalin-fixed paraffin-embedded (FFPE) slides were evaluated by two independent observers using light microscopy to categorise samples into three groups based on melanin content (no, low, or high) following a standardised system. The samples underwent the Idylla™ BRAF Mutation Test and were compared with results obtained from next-generation sequencing (NGS). Results: Quantification cycle (Cq) values were utilised to assess for interference from melanin levels on the Idylla™ BRAF Mutation Test results. Statistical analyses revealed no significant differences in Cq values based on melanin content categories. Furthermore, analysis of polymerase chain reaction PCR curves did not indicate any notable influence of melanin. Discordant results with NGS are discussed. Conclusions: The study demonstrates that melanin content in samples does not significantly affect the performance of the Idylla™ BRAF Mutation Test. These results provide robust evidence supporting the confident application of the test in clinical settings, even for samples with high melanin content. The ability to obtain rapid on-site results holds promising potential in guiding timely and appropriate treatment decisions, thereby contributing to improved patient prognosis. What is already known on this topic—Prior research conducted by Petty et al. (2020) including 23 melanoma samples suggested that melanin does not significantly interfere with the Idylla™ BRAF Mutation Test by stating they were concordant with reference laboratory testing. What this study adds—This current study builds upon prior research with a larger sample size of 98. In addition to examining concordance between the Idylla™ BRAF Mutation Test and next generation sequencing, this study examines PCR curves and effect on Cq values, providing more robust evidence that melanin content in FFPE samples does not have a significant impact on the accuracy of the Idylla™ BRAF Mutation Test. How this study might affect research, practice or policy—The additional evidence base provided by this study is valuable for researchers, clinicians, and policymakers, as it supports the integration of the Idylla™ BRAF Mutation Test as a rapid and accurate method for detecting these mutations in melanoma patients.

Advances in benchmarking and round robin testing for PEM water electrolysis: Reference protocol and hardware

While the number of publications in the PEM water electrolysis community increases each year, no common ground concerning reference hardware (test cells and test bench) and testing protocols has been yet established. This would, however, be necessary for the comparability of experimental results. First attempts for such reference hardware and procedures have been made in the framework of the Task 30 Electrolysis within the Technology Collaboration Programme on Advanced Fuel Cells (AFC TCP) of the International Energy Agency (IEA). Since then, improvements of both the test hardware (test cell and components) as well as the measurement protocol were identified, and a revised methodology and key results based on a comprehensive measurement series have been obtained. A detailed protocol for testing commercial reference components with a reference laboratory test cell developed in-house by Fraunhofer ISE is presented. For evaluation of the protocol and the hardware, it was tested at three different institutions at the same time. Impedance spectroscopic and polarization data was acquired and analyzed. The obtained differences in performance were calculated to give the community an expectation window to compare own data to. Finally, the importance of a thorough temperature control and the conditioning phase are demonstrated.

The impact of single gene testing (SGT) on subsequent comprehensive genomic profiling (CGP) success in community oncology practice for advanced non-small cell lung cancer (NSCLC): Results from a prospective observational reference laboratory testing program.

6506 Background: CGP concurrently tests tumor tissue for guideline-recommended predictive biomarkers for optimal therapy selection and identification of clinical trials in NSCLC patients. A common practice in the community oncology setting is to first order SGT, then consider CGP when SGT results are negative or after treatment failure. Given the limited tissue available and the scope of alterations not tested by SGT, we sought to characterize the effects of prior SGT on subsequent CGP testing success, and therapeutic opportunities identified by CGP beyond SGT for NSCLC patients in the community setting. Methods: Reference laboratory information systems were used to prospectively contact clinicians across 80 community practices who ordered at least 1 SGT for guideline-recommended genomic variants in NSCLC. CGP was offered for their patients prior to SGT or upon receipt of negative SGT results. SGT included individual assays for BRAF, EGFR, KRAS, MET exon 14 skipping mutations; ALK, RET, and ROS1 rearrangements; and PD-L1 IHC . CGP included DNA-seq for mutations, copy number variants in 523 genes including guideline-recommended genomic variants, MSI, and tumor mutational burden; RNA-seq for rearrangements/fusions/splice variants; and PD-L1 IHC. Results: Among a total of 580 NSCLC patients with CGP ordered (May 2021-December 2022), 168 (29%) had ≥1 SGT ordered prior to CGP (median=5). No patients had all SGT performed, with untested cases ranging from 10% for ALK to 90% for MET exon 14. The same FFPE tissue block was used for CGP in 150/168 (89%) of cases with prior negative SGT. Compared to CGP-only cases, CGP for cases with prior negative SGT was canceled twice as often at tissue review (16% vs 7%; p=.001), had higher DNA extraction failures (13% vs 8%; p=.09), and lower DNA sequencing success (70% vs 83%, p<.001). CGP detected guideline-recommended variants in 51% of all cases. Among prior negative SGT cases, frequencies were higher in genes where SGT was performed less often and is less sensitive than CGP RNA-seq ( RET fusions , MET exon 14 skipping). CGP also identified guideline-recommended variants in genes with no SGT offered during the study period ( ERBB2 mutations , NTRK2/3 fusions), as well as variants with emerging evidence for FDA expedited program-designated clinical trial therapies in 28% of patients, including NRG1 fusions and BRAF non-V600E , KEAP1, KRAS non-G12C, NFE2L2, STK11, and TP53 Y220C mutations. Conclusions: Prior negative SGT doubled subsequent CGP test cancellations for NSCLC due to tissue insufficiency and increased CGP DNA extraction failures. SGT practice in the community oncology setting does not meet practice guideline recommendations and negatively impacts the potential benefit of subsequent CGP for NSCLC patients.

Performance of clinical signs and symptoms, rapid and reference laboratory diagnostic tests for diagnosis of human African trypanosomiasis by passive screening in Guinea: a prospective diagnostic accuracy study

BackgroundPassive diagnosis of human African trypanosomiasis (HAT) at the health facility level is a major component of HAT control in Guinea. We examined which clinical signs and symptoms are associated with HAT, and assessed the performance of selected clinical presentations, of rapid diagnostic tests (RDT), and of reference laboratory tests on dried blood spots (DBS) for diagnosing HAT in Guinea.MethodThe study took place in 14 health facilities in Guinea, where 2345 clinical suspects were tested with RDTs (HAT Sero-K-Set, rHAT Sero-Strip, and SD Bioline HAT). Seropositives underwent parasitological examination (reference test) to confirm HAT and their DBS were tested in indirect enzyme-linked immunoassay (ELISA)/Trypanosoma brucei gambiense, trypanolysis, Loopamp Trypanosoma brucei Detection kit (LAMP) and m18S quantitative PCR (qPCR). Multivariable regression analysis assessed association of clinical presentation with HAT. Sensitivity, specificity, positive and negative predictive values of key clinical presentations, of the RDTs and of the DBS tests for HAT diagnosis were determined.ResultsThe HAT prevalence, as confirmed parasitologically, was 2.0% (48/2345, 95% CI: 1.5–2.7%). Odds ratios (OR) for HAT were increased for participants with swollen lymph nodes (OR = 96.7, 95% CI: 20.7–452.0), important weight loss (OR = 20.4, 95% CI: 7.05–58.9), severe itching (OR = 45.9, 95% CI: 7.3–288.7) or motor disorders (OR = 4.5, 95% CI: 0.89–22.5). Presence of at least one of these clinical presentations was 75.6% (95% CI: 73.8–77.4%) specific and 97.9% (95% CI: 88.9–99.9%) sensitive for HAT. HAT Sero-K-Set, rHAT Sero-Strip, and SD Bioline HAT were respectively 97.5% (95% CI: 96.8–98.1%), 99.4% (95% CI: 99.0–99.7%) and 97.9% (95% CI: 97.2–98.4%) specific, and 100% (95% CI: 92.5–100.0%), 59.6% (95% CI: 44.3–73.3%) and 93.8% (95% CI: 82.8–98.7%) sensitive for HAT. The RDT’s positive and negative predictive values ranged from 45.2–66.7% and 99.2–100% respectively. All DBS tests had specificities ≥ 92.9%. While LAMP and m18S qPCR sensitivities were below 50%, trypanolysis and ELISA/T.b. gambiense had sensitivities of 85.3% (95% CI: 68.9–95.0%) and 67.6% (95% CI: 49.5–82.6%).ConclusionsPresence of swollen lymph nodes, important weight loss, severe itching or motor disorders are simple but accurate clinical criteria for HAT referral in HAT endemic areas in Guinea. Diagnostic performances of HAT Sero-K-Set and SD Bioline HAT are sufficient for referring positives to microscopy. Trypanolysis on DBS may discriminate HAT patients from false RDT positives.Trial registration The trial was registered under NCT03356665 in clinicaltrials.gov (November 29, 2017, retrospectively registered https://clinicaltrials.gov/ct2/show/NCT03356665)Graphical

A Ten-Year Retrospective Survey of Antimicrobial Susceptibility Patterns among Salmonella enterica subsp. enterica Serovar Typhi Isolates in Ontario, Canada.

The epidemiology and treatment of typhoid fever are complicated by the emergence and spread of Salmonella enterica subsp. enterica serovar Typhi lineages with resistance to many antimicrobial agents critical for therapy. Current information on the susceptibility patterns of S. Typhi isolates identified in regions where typhoid fever is not endemic is important as these are often acquired after traveling to countries of endemicity where resistant strains circulate. Here, we report a 10-year retrospective survey of S. Typhi antimicrobial susceptibility patterns among 858 unique patient isolates that underwent reference laboratory testing in Ontario, Canada, between 2010 and 2019. Antimicrobial susceptibility patterns remained stable for ampicillin (average, 78.7% susceptible), azithromycin (average, 99.4% susceptible) ertapenem (average, 100.0% susceptible), meropenem (average, 100.0% susceptible), and trimethoprim-sulfamethoxazole (average, 78.2% susceptible) during the study period; however, nonsusceptibility to ciprofloxacin and ceftriaxone increased. While ceftriaxone-resistant isolates comprised 1.6% of the total isolates overall, they represented 10.1% of the total isolates tested in 2019, indicating a significant increase over time. Our findings suggest that when selecting empirical therapy, health care providers should strongly consider current trends in antimicrobial susceptibility and investigate the patient's exposure risk to gauge whether a suspected typhoid infection may be caused by a potentially resistant S. Typhi strain. IMPORTANCE This work provides an updated summary of the antimicrobial susceptibility patterns among Salmonella Typhi strains isolated from patients in Ontario, Canada.

Comparing variability in diagnosis of upper respiratory tract infections in patients using syndromic, next generation sequencing, and PCR-based methods.

Early and accurate diagnosis of respiratory pathogens and associated outbreaks can allow for the control of spread, epidemiological modeling, targeted treatment, and decision making-as is evident with the current COVID-19 pandemic. Many respiratory infections share common symptoms, making them difficult to diagnose using only syndromic presentation. Yet, with delays in getting reference laboratory tests and limited availability and poor sensitivity of point-of-care tests, syndromic diagnosis is the most-relied upon method in clinical practice today. Here, we examine the variability in diagnostic identification of respiratory infections during the annual infection cycle in northern New Mexico, by comparing syndromic diagnostics with polymerase chain reaction (PCR) and sequencing-based methods, with the goal of assessing gaps in our current ability to identify respiratory pathogens. Of 97 individuals that presented with symptoms of respiratory infection, only 23 were positive for at least one RNA virus, as confirmed by sequencing. Whereas influenza virus (n = 7) was expected during this infection cycle, we also observed coronavirus (n = 7), respiratory syncytial virus (n = 8), parainfluenza virus (n = 4), and human metapneumovirus (n = 1) in individuals with respiratory infection symptoms. Four patients were coinfected with two viruses. In 21 individuals that tested positive using PCR, RNA sequencing completely matched in only 12 (57%) of these individuals. Few individuals (37.1%) were diagnosed to have an upper respiratory tract infection or viral syndrome by syndromic diagnostics, and the type of virus could only be distinguished in one patient. Thus, current syndromic diagnostic approaches fail to accurately identify respiratory pathogens associated with infection and are not suited to capture emerging threats in an accurate fashion. We conclude there is a critical and urgent need for layered agnostic diagnostics to track known and unknown pathogens at the point of care to control future outbreaks.

Determination of quality attributes and ripening stage using vis-nir spectroscopy in intact seriguela and umbu fruits

To produce seriguela and umbu on a large scale, it is important to detect the ripening stages and quality attributes of the fruits, to define the ideal harvest point. Thus, this study aimed to determine, in a non-destructive way, the quality attributes and ripening stages of intact seriguela and umbu fruits using Vis-NIR spectroscopy. A total of 150 seriguela fruits and 150 umbu fruits were used, at different ripening stages, and subjected to spectral analysis and reference laboratory testing to determine total soluble solids (TSS) and firmness. Spectral data were subjected to different pre-processing techniques. Regression and classification models were created through the statistical learning and machine learning methods. The models with the best performance for TSS were RF (R2P = 0.94) and PLSR (R2P = 0.68), and for firmness were PLSR (R2P = 0.92) and RF (R2P = 0.58), for seriguela and umbu, respectively. The model with the best performance in the classification was LDA, with a precision greater than 95% to discriminate the ripening stages of both fruits. Therefore, the Vis-NIR spectroscopy is a potential tool to determine the quality attributes and ripening stages, in a non-destructive way, of intact seriguela and umbu fruits.

Direct shear behavior of gravel-rubber mixtures: Discrete element modeling and microscopic investigations

In this paper, a newly developed 3-dimentional discrete element model (DEM) for gravel-rubber mixtures (GRMs), namely DEM4GRM, that is capable of accurately describing the macro-scale shear response (from small to large deformation) of GRMs in a direct shear box apparatus is presented. Rigid gravel grains are modelled as simple multi-shape clumps, while soft rubber particles are modeled by using deformable 35-ball body-centered-cubic clusters. Mixtures are prepared with different volumetric rubber content (VRC) at 0, 10, 25, 40 and 100%, statically compressed under 30, 60 and 100 kPa vertical stress and then sheared, by closely simulating a reference laboratory test procedure. The variation of micro-scale factors such as fabric, normal and tangential force anisotropy is carefully examined throughout the shearing process and described by means of novel micro-mechanical relationships valid for GRMs. Moreover, strong-force chains are scrutinized to identify the transition from rigid to soft granular skeleton and gain insights on the load transfer and deformation mechanisms of GRMs. It is shown that the development of the fabric and force anisotropy during shearing is closely related to the macro-scale shear strength of GRMs, and strongly depends on the VRC. Besides, strong-force chains appear to be primarily formed by gravel-gravel contacts (resulting in a rigid-like mechanical behavior) up to VRC = 30%, and by rubber-rubber contacts (causing a soft-like mechanical response) beyond VRC = 60%. Alternatively, at 30% <VRC < 60%, gravel-rubber contacts are predominant in the strong-force network and an intermediate mechanical behavior is observed. This is consistent with the behavioral trends observed in the macro- and micro-mechanical responses.

Displaying Cost and Completion Time for Reference Laboratory Test Orders-A Randomized Controlled Trial.

Reduction in unnecessary services is one strategy for increasing the value of health care. Reference laboratory, or send-out, tests are associated with considerable costs. We investigated whether displaying cost and turnaround time (TAT), or time-to-result, for reference laboratory tests at the time of order entry in the electronic health record (EHR) system would impact provider ordering practices. Reference laboratory test cost and TAT data were randomized prior to the study and only displayed for the intervention group. A 24-month dataset composed of 12 months each for baseline and study periods was extracted from the clinical data mart. A difference-in-differences (DID) analysis was conducted using a linear mixed-effects model to estimate the association between the intervention and changes in test-ordering patterns. In the inpatient setting, the DIDs of aggregate test-order costs and volume were not different among the control and intervention groups (p = 0.31 and p = 0.26, respectively). In the ambulatory setting, the DIDs of aggregate test-order costs and volume were not different among the control and intervention groups (p = 0.82 and p = 0.51, respectively). For both inpatient and ambulatory settings, no significant difference was observed in the DID of aggregate test-order costs and volumes calculated in respect to stratified relative cost and TAT groups (p > 0.05). Lack of alternative tests, test orders placed at a late step in patient management, and orders facilitated by trainees or mid-level providers may have limited the efficacy of the intervention. Our randomized study demonstrated no significant association between the display of cost or TAT display and ordering frequency.

Establishment of Hematological Reference Values among Healthy Adults in Bamenda, North West Region of Cameroon.

The use of the reference range of values of a laboratory test is highly significant in diagnostic accuracy. However, race and ethnic variations may affect the safe use of reference ranges from a different setting/population. Because the establishment of reference ranges for the Cameroonian population will possibly improve the quality of health care, this study was designed to establish hematological reference ranges among healthy adults in Bamenda, North West region of Cameroon. This was a cross-sectional study carried out within the period of five months from February 2020 to June 2020, at the Bamenda Regional Hospital. A total of 350 (139 females and 211 males) study participants who met the inclusion criteria were included in the study. The Urit 3300 autoanalyzer (Urit Medical Electronic (Group) Co., Ltd, Guilin, China) was used to analyze the hematological parameters. The general health questionnaire for donors, for verification of reference range study and laboratory tests, was used for data collection. Descriptive statistics were used to calculate reference ranges, means, and medians at 95% confidence intervals. Maximum and minimum reference ranges were computed at 97.5th and 2.5th percentiles. The nonparametric test (Mann–Whitney test) was used to determine the significance of the difference in hematological values between the male and female groups. Three (MID%, LYM#, and MID#) out of the 19 hematological parameters were verified, while sixteen (WBC, LYM%, GRAN%, GRAN#, RBC, HGB, HCT%, MCV, MCH, MCHC, RDW_CV, RDW_SD, PLT, MPV, PDW, and PCT%) were established. The currently used reference intervals do not represent the population of the North West region. Therefore, other regional hospitals in Cameroon should establish reference intervals applicable to their respective regions.

Engaging Pathology Residents in Clinical Chemistry: The Essential Ingredient Is a Committed Teacher.

Pathology residents are thought to show a lack of interest in clinical chemistry, therefore potentially graduating from training programs unprepared to function as laboratory directors and clinical consultants. A structured program of tutorials based primarily on Henry's textbook, supplemented by recent review articles; a question bank of about 600 questions to emphasize key concepts; requirement for performing and presenting quality improvement projects; participation in on-site CAP inspections; review of reference laboratory test requests; and involving residents in scholarly activity have resulted in sustained, transferable, and significant improvements in engagement, knowledge, competence, and examination scores. The primary parameter for measuring change in resident competence and engagement were improvements in resident in-service examination (RISE) scores, publications in peer-reviewed journals, and receipt of awards. The revised program produced significant improvement in RISE scores in clinical chemistry, over and above the improvements in the general residency program. The residents were authors on 12 publications in peer-reviewed PubMed listed journals in the 5-year period since revision in the clinical chemistry curriculum compared to no publications in clinical chemistry in the 5-year period before the new curriculum. Over the past 2 years, 6 of the 11 publications by graduating residents were in clinical chemistry, and 6 of 7 awards for research were garnered by residents engaged in clinical chemistry investigations. All of the residents passed their clinical pathology boards on first attempt since the change compared to 2 failures in the prior 5-year period. The structured program described here is important as a template that could be adopted by any pathology training program. The question bank developed by this program is a valuable and transferable aid. However, success of such a program is dependent on the commitment of a knowledgeable, dedicated, and passionate teacher.

Persistent Hepatitis E virus infection across England and Wales 2009-2017: Demography, virology and outcomes.

The first clinical case of persistent HEV infection in England was reported in 2009. We describe the demography, virology and outcomes of patients identified with persistent HEV infection in England and Wales between 2009 and 2017. A series of 94 patients with persistent HEV infection, defined by HEV viraemia of more than 12weeks, was identified through routine reference laboratory testing. Virology, serology and clinical data were recorded through an approved PHE Enhanced Surveillance System. Sixty-six cases (70.2%) were transplant recipients, 16 (17.0%) had an underlying haematological malignancy without stem cell transplantation, six (6.4%) had advanced HIV infection, five (5.3%) were otherwise immunosuppressed, and one patient (1.1%) had no identified immunosuppression. Retrospective analysis of 46 patients demonstrated a median 38weeks of viraemia before diagnostic HEV testing. At initial diagnosis, 16 patients (17.0%) had no detectable anti-HEV serological response. Of 65 patients treated with ribavirin monotherapy, 11 (16.9%) suffered virological relapse despite undetectable RNA in plasma or stool at treatment cessation. Persistent HEV infection remains a rare diagnosis, but we demonstrate that a broad range of immunocompromised patients are susceptible. Both lack of awareness and the pauci-symptomatic nature of persistent HEV infection likely contribute to significant delays in diagnosis. Diagnosis should rely on molecular testing since anti-HEV serology is insufficient to exclude persistent HEV infection. Finally, despite treatment with ribavirin, relapses occur even after cessation of detectable faecal shedding of HEV RNA, further emphasising the requirement to demonstrate sustained virological responses to treatment.

Prevalence of heartworm in relocated, local and outreach clinic dogs: A Canadian sheltering perspective

This study reports heartworm (Dirofilaria immitis) prevalence in dogs tested by an animal shelter located in a low-prevalence region of Ontario, Canada. From 2015–2018, 4567 unique dogs were tested. The prevalence of heartworm was 3.9 %, with sub-prevalence of 0.3 % (2/662) for dogs surrendered within the Greater Toronto Area (both dogs were originally imported from the US); 6.6 % (130/1,981) for dogs relocated from beyond the Greater Toronto Area; 0% (0/1,668) for dogs tested at the shelter’s public veterinary services clinic and 18.4 % (47/256) for owned dogs tested at outreach clinics at a First Nations community in south-eastern Ontario. More than half (54.7 %) of the heartworm-positive dogs originated from Canada. Most heartworm-positive dogs from the US (72/80; 90 %) were transferred from Texas and Georgia.Ninety-three heartworm-positive Canadian dogs were from Ontario, 4 from Manitoba and 1 from Quebec. Most (83/98, 84.7 %) were from four First Nations communities. The prevalence in homeless dogs from one First Nations community in south-western Ontario was 36.5 % (31/85).For 140 shelter dogs with at least one positive test result, there was 91 % concordance between shelter and reference laboratory antigen tests and poor agreement between antigen tests and microfilarial tests (approximately 50 %). Results of historical tests and post-relocation antigen tests were discordant in 28.2 % (shelter point-of-care tests) and 36.2 % (reference laboratory tests) of cases. This was most commonly due to negative historical results followed by positive results after relocation. Microfilarial filtration tests were positive for 77.1 % antigen-positive dogs from First Nations communities, compared with 37.1 % of dogs from other sources. Microfilarial counts were significantly higher for dogs from First Nations communities.This study demonstrated endemic and hyperendemic foci of heartworm within Canada, which were presumed to be associated with limited access to veterinary care. The results support recommendations to retest previously negative animals after relocation.