Effect of the technical variability of counting chambers upon the interpretation of sperm concentration results.

RESEARCH QUESTION: Does the choice of sperm-counting chamber affect the proportion of samples generating results with an erroneous interpretation? DESIGN: Laboratories in an external quality assurance programme were sent 141 semen samples over a 12-year period and asked to return the sperm concentration and whether or not the result was abnormal. Only those using 5th edition of the World Health Organization manual (WHO5) interpretation criteria were included. Submissions from specialist fertility laboratories were used to calculate assigned values for each sample. Laboratory50 values determined the sperm concentration at which the laboratories reported a majority transition from abnormal to normal interpretations, i.e. the tipping point, which should coincide with the lower reference limit. RESULTS: The median and range of bias from the assigned values of each sample were determined for the Makler (-3.3%; -88.6% to +332.8%), haemocytometer (10.6%; -93.3% to +645.5%), Kova (+65.3%; -71.7% to +581.8%) and Vetriplast (+72.4%; -100.0% to +709.1) chambers. Laboratory50 values for the Makler (17.3  ×  106/ml), haemocytometer (13.6  ×  106/ml), Kova (10.0  ×  106/ml) and Vetriplast chambers (8.8  ×  106/ml) reflected the under- and overestimation of the chambers and confirmed a shift in the adjusted lower reference limit then used. The proportion of laboratories reporting erroneous interpretations of the four chambers for oligozoospermic samples were 10.9%, 15.1.%, 40.1% and 44.0%, respectively, and rose as the adjusted lower reference limit decreased. CONCLUSIONS: The between-laboratory and within-sample variation for all the chambers was high and remains a concern. The main impact of an increasing bias of the chambers was a lowering of the laboratory50 tipping point, resulting in an under-reporting of abnormal semen samples.

An Unexpected Diagnosis Uncovered by Quantitative Molecular Findings: A Case Report.

A 74-year-old male presented with rectal pain; workup uncovered an anal mass, and a diagnosis of melanoma was rendered via histologic examination and immunohistochemical (IHC) studies. Droplet digital PCR (ddPCR)-based BRAF testing was performed and revealed the presence of BRAF V600E, which is a common targetable genetic alteration in melanoma. Interestingly, the ratio of mutant to wild-type copy number was low (0.3%), whereas tumor cell percentage on tissue slides was 90%. With additional workup, BRAF V600E IHC confirmed a very small subset of BRAF V600E-positive cells, and a next-generation sequencing (NGS) panel revealed a pathogenic KIT variant, p.L576P, with an allele frequency of 63%. It was initially hypothesized that the main driver of the melanoma was the KIT alteration, whereas a small subclone (not detected by NGS, which has a 5% limit of detection) was driven by the BRAF V600E detected by ddPCR. To determine whether there were morphologic differences between the 2 clones, a careful review of the histology was performed and revealed distinct morphology of the BRAF V600E-positive cells, including pale cytoplasm, nuclear grooves, and infiltrating eosinophils. Additional IHC workup of the BRAF V600E-positive cells showed coexpression of CD1a, Langerin, and S100, diagnostic of Langerhans cell histiocytosis (LCH). This diagnosis was unexpected and would have been missed without highly sensitive molecular testing; yet it is of clinical importance for the patient. This case raises interesting biology questions regarding the relationship between melanoma and LCH; moreover, it highlights the importance of integrating quantitative information in molecular data interpretation.

Pathogenesis of COVID-19 and the quality control of nucleic acid detection.

The new coronavirus pneumonia (COVID-19) epidemic spread rapidly throughout the world. Considering the strong infectivity and clustering of COVID-19, early detection of infectious cases is of great significance to control the epidemic. Nucleic acid testing (NAT) plays an important role in rapid laboratory diagnosis, treatment assessment, epidemic prevention and control of COVID-19. However, since COVID-19 is caused by a new emerging virus and NAT for COVID-19 has not been clinically applied before, false negative results inconsistent with clinical diagnosis have appeared in clinical practice. Therefore, it is urgent to improve the sensitivity of NAT for COVID-19. This study aimed to summarize the current situation and prospect of NAT based on the latest findings on COVID-19 infection. Also, the quality control of sample collection was discussed. Hopefully, this study could help to improve the effectiveness of NAT for COVID-19.

Laboratory Diagnosis of COVID-19: Current Issues and Challenges.

The COVID-19 outbreak has had a major impact on clinical microbiology laboratories in the past several months. This commentary covers current issues and challenges for the laboratory diagnosis of infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In the preanalytical stage, collecting the proper respiratory tract specimen at the right time from the right anatomic site is essential for a prompt and accurate molecular diagnosis of COVID-19. Appropriate measures are required to keep laboratory staff safe while producing reliable test results. In the analytic stage, real-time reverse transcription-PCR (RT-PCR) assays remain the molecular test of choice for the etiologic diagnosis of SARS-CoV-2 infection while antibody-based techniques are being introduced as supplemental tools. In the postanalytical stage, testing results should be carefully interpreted using both molecular and serological findings. Finally, random-access, integrated devices available at the point of care with scalable capacities will facilitate the rapid and accurate diagnosis and monitoring of SARS-CoV-2 infections and greatly assist in the control of this outbreak.

[Selective internal pudendal arteriography in the diagnosis of arteriogenic erectile dysfunction].

OBJECTIVE: To explore the procedure of selective internal pudendal arteriography (IPA) and its application in the diagnosis of arteriogenic erectile dysfunction (AED). METHODS: We performed selective IPA for 62 patients highly suspected of AED with abnormal nocturnal penile tumescence (NPT) and peak systolic velocity (PSV) of the penile cavernosal artery < 25 ml/s. Using digital subtraction angiography, we assessed the stenosis of the main internal pudendal artery and measured the lengths of the dorsal penile arteries and cavernosal arteries. RESULTS: Of the total number of patients, 21 were found with normal internal pudendal arteries, dorsal penile arteries and cavernosal arteries, 7 with abnormal pudendal arteries and atherosclerotic lesions, 37 with inadequately visualized dorsal penile arteries and/or cavernosal arteries, and 3 with both abnormal pundendal and dorsal penile arteries or inadequately visualized cavernosal arteries. No complications were observed except for 3 cases of subcutaneous hematoma at the puncture site. CONCLUSIONS: Selective IPA can display the morphological features of internal pudendal, dorsal penile and cavernosal arteries and help to localize arterial lesions and evaluate blood supply in the penile artery. Therefore, it is a safe and reliable method for the diagnosis of AED.

Updated Czech guidelines for the laboratory diagnosis of Clostridium difficile infections.

Clostridium difficile, a causative agent of intestinal infections (CDI) of varying severity, is an important nosocomial pathogen. Microbiological diagnosis, including an appropriate test algorithm and the corresponding interpretation of the results, is crucial for CDI confirmation. This update is based on the European guidance document for CDI laboratory diagnosis, taking into account the current CDI epidemiology and laboratory diagnostic approaches in the Czech Republic. Any diarrhoeal patient should be tested for CDI. The rectal swabs can only be used for testing in patients with paralytic ileus. Currently, a two-step test algorithm is recommended for CDI diagnosis. Due to a low positive predictive value, a single commercial test is not recommended as a stand-alone test for diagnosing CDI. Samples with a positive screening test (glutamate dehydrogenase or toxigenic strain nucleic acid) and a subsequent negative EIA (enzyme immunoassay) test for the presence of free toxins are diagnostically inconclusive. An option is to use a third confirmatory test; however, the current clinical status of the patient along with other laboratory findings should be considered in order to differentiate between ongoing CDI, carriage of a toxigenic strain of C. difficile, and other causes of diarrhoea. In general, when implementing a new diagnostic test, its sensitivity and specificity should be compared against the reference method. Diagnostic tests should refer to the data from published comparative studies and should not rely solely on information provided by the manufacturer. Currently, there is no commercial test available for detection of free C. difficile toxins in stool samples with 100 % sensitivity. Moreover, the pre-analytical conditions (storage and transport temperature of stool samples) and/or the initiation of an empirical therapy prior to the sampling may decrease the sensitivity of the assay.

From autoantibody test results to decision making: Incorporating likelihood ratios within medical practice.

Autoantibodies are important laboratory markers to support diagnosis of autoimmune diseases. Interpretation of autoantibodies is classically done in a dichotomous way (positive versus negative). Yet, interpretation of autoantibody test results can be improved by reporting likelihood ratios. Likelihood ratios convey information on how much more/less likely a test result is in individuals with the disease compared to individuals without the disease. It incorporates information on the antibody level (the higher the antibody level, the higher the association with the disease), which is helpful for (differential) diagnosis. Likelihood ratios are unit-independent and allow users to harmonize test result interpretation. When the likelihood ratio is combined with information on the pre-test probability, post-test probability can be appraised. In this review, the applicability of likelihood ratio in autoimmune diagnostics will be reviewed from the perspective of the clinician, the laboratory professional and the in vitro diagnostic industry.

Can artificial intelligence replace biochemists? A study comparing interpretation of thyroid function test results by ChatGPT and Google Bard to practising biochemists.

BACKGROUND: Public awareness of artificial intelligence (AI) is increasing and this novel technology is being used for a range of everyday tasks and more specialist clinical applications. On a background of increasing waits for GP appointments alongside patient access to laboratory test results through the NHS app, this study aimed to assess the accuracy and safety of two AI tools, ChatGPT and Google Bard, in providing interpretation of thyroid function test results as if posed by laboratory scientists or patients. METHODS: Fifteen fictional cases were presented to a team of clinicians and clinical scientists to produce a consensus opinion. The cases were then presented to ChatGPT and Google Bard as though from healthcare providers and from patients. The responses were categorized as correct, partially correct or incorrect compared to consensus opinion and the advice assessed for safety to patients. RESULTS: Of the 15 cases presented, ChatGPT and Google Bard correctly interpreted only 33.3% and 20.0% of cases, respectively. When queries were posed as a patient, 66.7% of ChatGPT responses were safe compared to 60.0% of Google Bard responses. Both AI tools were able to identify primary hypothyroidism and hyperthyroidism but failed to identify subclinical presentations, non-thyroidal illness or secondary hypothyroidism. CONCLUSIONS: This study has demonstrated that AI tools do not currently have the capacity to generate consistently correct interpretation and safe advice to patients and should not be used as an alternative to a consultation with a qualified medical professional. Available AI in its current form cannot replace human clinical knowledge in this scenario.

Public knowledge of SARS-CoV-2 serological and viral lineage laboratory testing and result interpretation: A GENCOV study cross-sectional survey.

OBJECTIVES: Concepts related to SARS-CoV-2 laboratory testing and result interpretation can be challenging to understand. A cross-sectional survey of COVID-19 positive adults residing in Ontario, Canada was conducted to explore how well people understand SARS-CoV-2 laboratory tests and their associated results. DESIGN AND METHODS: Participants were recruited through fliers or by prospective recruitment of outpatients and hospitalized inpatients with COVID-19. Enrolled participants included consenting adults with a positive SARS-CoV-2 polymerase chain reaction test result. An 11-item questionnaire was developed by researchers, nurses, and physicians in the study team and was administered online between April 2021 to May 2022 upon enrolment into the study. RESULTS: Responses were obtained from 940 of 1106 eligible participants (85% participation rate). Most respondents understood 1) that antibody results should not influence adherence to social distancing measures (n = 602/888, 68%), 2) asymptomatic SARS-CoV-2 infection following test positivity (n = 698/888, 79%), 3) serological test sensitivity in relation to post-infection timeline (n = 540/891, 61%), and 4) limitations of experts' knowledge related to SARS-CoV-2 serology (n = 693/887, 78%). Conversely, respondents demonstrated challenges understanding 1) conflicting molecular and serological test results and their relationship with immune protection (n = 162/893, 18%) and 2) the impact of SARS-CoV-2 variants on vaccine effectiveness (n = 235/891, 26%). Analysis of responses stratified by sociodemographic variables identified that respondents who were either: 1) female, 2) more educated, 3) aged 18-44, 4) from a high-income household, or 5) healthcare workers responded expectedly more often. CONCLUSIONS: We have highlighted concepts related to SARS-CoV-2 laboratory tests and associated results which may be challenging to understand. The findings of this study enable us to identify 1) misconceptions related to various SARS-CoV-2 test results, 2) groups of individuals at risk, and 3) strategies to improve people's understanding of their test results.

Different approaches for estimating measurement uncertainty: An effective tool for improving interpretation of results.

BACKGROUND: The estimation of measurement uncertainty (MU) in clinical laboratories is of crucial importance in improving laboratory testing quality and correctly interpreting results. However, it is difficult for clinical laboratories to reliably estimate MU since current guidelines and standards fail to clearly define and harmonize methods to be used for this purpose. AIMS: To propose a model for MU estimation in relation to test interpretation on the basis of three different scenarios. METHODS: MU estimation was evaluated regard to the inclusion of imprecision and bias components for different test purposes. RESULTS: Three scenarios were identified. The expanded uncertainty values were: 0.56 ng/L and 1.86 ng/L for troponin I at levels 4.95 ng/L and 20.60 ng/L, respectively; 9.4 µmol/L and 27.2 µmol/L for creatinine at levels 121.0 µmol/L and 390.0 µmol/L, respectively. 0.2 mmol/L and 0.3 mmol/L for potassium at levels 4.03 mmol/L and 6.35 mmol/L, respectively; 0.36 mmol/L for glucose at level of around 6 mmol/L. These values represent MU results estimated for the three scenarios, which contemplate test results used for 1a) short term patient monitoring, 1b) longer term patient monitoring, 2) comparison with reference intervals and 3) comparison with a clinical decision point. CONCLUSIONS: Goal-based measurement uncertainty estimation in clinical laboratories provides an opportunity to improve laboratory testing quality and reduce risk in the interpretation of clinical results.

National Survey of Adult and Pediatric Reference Intervals in Clinical Laboratories across Canada: A Report of the CSCC Working Group on Reference Interval Harmonization.

OBJECTIVE: Reference intervals are widely used decision-making tools in laboratory medicine, serving as health-associated standards to interpret laboratory test results. Numerous studies have shown wide variation in reference intervals, even between laboratories using assays from the same manufacturer. Lack of consistency in either sample measurement or reference intervals across laboratories challenges the expectation of standardized patient care regardless of testing location. Here, we present data from a national survey conducted by the Canadian Society of Clinical Chemists (CSCC) Reference Interval Harmonization (hRI) Working Group that examines variation in laboratory reference sample measurements, as well as pediatric and adult reference intervals currently used in clinical practice across Canada. DESIGN AND METHODS: Data on reference intervals currently used by 37 laboratories were collected through a national survey to examine the variation in reference intervals for seven common laboratory tests. Additionally, 40 clinical laboratories participated in a baseline assessment by measuring six analytes in a reference sample. RESULTS: Of the seven analytes examined, alanine aminotransferase (ALT), alkaline phosphatase (ALP), and creatinine reference intervals were most variable. As expected, reference interval variation was more substantial in the pediatric population and varied between laboratories using the same instrumentation. Reference sample results differed between laboratories, particularly for ALT and free thyroxine (FT4). Reference interval variation was greater than test result variation for the majority of analytes. CONCLUSION: It is evident that there is a critical lack of harmonization in laboratory reference intervals, particularly for the pediatric population. Furthermore, the observed variation in reference intervals across instruments cannot be explained by the bias between the results obtained on instruments by different manufacturers.

Métodos diagnósticos para la infección por SARS-CoV-2 / Diagnostic methods for SARS-CoV-2 infection

En diciembre de 2019 se identificó el virus SARS-CoV-2, cuya rápida propagación global puso en estado de emergencia al mundo entero, llevando al ser humano a una situación sin antecedente cercano. El objetivo de esta revisión es describir los métodos diagnósticos utilizados actualmente para identificar la infección por SARS-CoV-2. Las manifestaciones clínicas y el espectro imagenológico de la enfermedad son muy inespecíficos y no permiten realizar un diagnóstico certero. Por esta razón, es esencial una apropiada toma de muestra respiratoria en el momento y sitio anatómico adecuado para un diagnóstico preciso de COVID-19. La técnica de muestreo más utilizada es el hisopado nasofaríngeo y la prueba diagnóstica más fiable se basa en la retrotranscripción seguida por reacción en cadena de la polimerasa en tiempo real (RT-PCR). No obstante, existen otras técnicas moleculares, como también tests serológicos para detectar anticuerpos o fragmentos antigénicos del SARS-CoV-2. Más allá de la precisión diagnóstica, es importante tener en cuenta la probabilidad basal (pretest) para interpretar correctamente el resultado obtenido y aislar aquellos posibles falsos negativos. Con el objetivo de evitar la saturación del sistema de salud es imprescindible contar con información y métodos diagnósticos precisos para detectar tempranamente los focos de infección y reducir la transmisión comunitaria, utilizando eficazmente los diferentes recursos diagnósticos. (AU)

In December 2019, the SARS-CoV-2 virus was identified for the first time, whose rapid global spread put the entire world in a state of emergency, leading humans to an unprecedented situation with no immediate history. The main purpose of this review is to describe the diagnostic methods currently used to identify SARS-CoV-2 infection. The clinical manifestations and the imaging spectrum of the disease are nonspecific and do not allow an accurate diagnosis to be made. For this reason, an appropriate respiratory sampling at the right time and anatomical site is essential for an accurate diagnosis of COVID-19. The most widely used sampling technique is nasopharyngeal swab, and the most reliable diagnostic test is by reverse transcription followed by real-time polymerase chain reaction (RT-PCR). However, there are other molecular techniques, as well as serological tests to detect antibodies or antigenic fragments of SARS-CoV-2. Beyond the diagnostic precision, it is important to take into account the baseline probability (pre-test) to correctly interpret the result obtained and isolate those possible false negatives. In order to avoid saturation of the health system, it is essential to have accurate information and diagnostic methods to detect outbreaks of infection in early stages and to reduce communitary transmission, making effective use of the various diagnostic resources. Coronavirus infections/diagnosis, viral/diagnosis, pandemics, clinical laboratory techniques, real-time polymerase chain reaction, antigens, viral/analysis. (AU)

Review of LCA studies of solid waste management systems--part I: lessons learned and perspectives.

The continuously increasing solid waste generation worldwide calls for management strategies that integrate concerns for environmental sustainability. By quantifying environmental impacts of systems, life cycle assessment (LCA) is a tool, which can contribute to answer that call. But how, where and to which extent has it been applied to solid waste management systems (SWMSs) until now, and which lessons can be learnt from the findings of these LCA applications? To address these questions, we performed a critical review of 222 published LCA studies of SWMS. We first analysed the geographic distribution and found that the published studies have primarily been concentrated in Europe with little application in developing countries. In terms of technological coverage, they have largely overlooked application of LCA to waste prevention activities and to relevant waste types apart from household waste, e.g. construction and demolition waste. Waste management practitioners are thus encouraged to abridge these gaps in future applications of LCA. In addition to this contextual analysis, we also evaluated the findings of selected studies of good quality and found that there is little agreement in the conclusions among them. The strong dependence of each SWMS on local conditions, such as waste composition or energy system, prevents a meaningful generalisation of the LCA results as we find it in the waste hierarchy. We therefore recommend stakeholders in solid waste management to regard LCA as a tool, which, by its ability of capturing the local specific conditions in the modelling of environmental impacts and benefits of a SWMS, allows identifying critical problems and proposing improvement options adapted to the local specificities.

Significant, quantifiable differences exist between IgG subclass standards WHO67/97 and ERM-DA470k and can result in different interpretation of results.

OBJECTIVES: Accurate measurement of IgG subclass (IgGSc) levels are essential to aid in the diagnosis of disease states such as primary immunodeficiencies. However, there is no single standardisation of nephelometric and turbidimetric assays for these analytes and two reference materials have been utilised. We expand on previous reports and present data from a multi-site analysis that both identifies and quantitatively defines the differences in calibration resulting from the use of different reference materials. DESIGN AND METHODS: IgGSc antibodies in the serum specimens and reference materials were measured according to the manufacturers' instructions using commercially available IgGSc assays or components. RESULTS: Data from four independent sites showed that in spite of the different commercial suppliers of IgGSc assays calibrating to different reference materials, ERM-DA470k and WHO67 /97, the resulting calibrations were comparable for IgG1 and IgG2. However, for IgG3 and IgG4 the calibrations were significantly different. The use of assay specific normal ranges should compensate for these calibration differences, however, the two manufacturers' assays can give differing clinical classifications. The agreement between the different manufacturers' IgGSc assays was between 85.1% and 95.8% for all IgGSc assays, the discordance of sample classification for IgG1 and IgG2 assays was approximately 12% and 15% respectively, whilst that for IgG3 and IgG4 was 4% and 13% respectively. CONCLUSION: We discuss the similarities and differences between assays that utilise the different reference materials.