Laboratory specimen rejection rate and associated factors among referred specimens at Debre Markos Referral Hospital, Ethiopia: prospective cross-sectional study.

Introduction: laboratory errors mostly emerge from the pre-analytical phase, mainly those related to collection, handling, transportation, and storage of diagnostic specimens. Specimen rejection due to improper sample collection, may lead to poor patient outcomes, such as incorrect diagnosis, inappropriate treatment, and death. This study aimed to assess the specimen rejection rate and associated factors among referred specimens at Debre Markos Referral Hospital. Methods: a prospective cross-sectional study design was applied from January 2020 to April 2020 to investigate specimen rejection rate and associated factors among referred specimens. The study population was all laboratory specimens referred for viral load, CD4 count, gene expert, and early infant diagnosis to the Debre Markos Referral Hospital laboratory. The statistical analysis was done with Statistical Package for Social Sciences version 20.0 software. Results: of the total of 2750 specimens submitted to the laboratory from January 2020 to April 2020, 37 (1.34%) specimens were rejected due to different reasons like insufficient volume, hemolysis, and an inappropriate specimen container. Specimen collector training status and experience had a significant association with the specimen rejection rate. Conclusion: the results of our study show that the specimen rejection rate among referred specimens was high, indicating that more interventions are required to decrease the specimen rejection rate.

Critical test result management at Danish hospital laboratories: a national survey.

Critical test results in clinical laboratories are crucial for timely patient care, serving as indicators of potentially life-threatening conditions. Despite their importance, a notable heterogeneity in management practices exists globally. This study investigates the current practices of managing critical results at Danish clinical biochemistry laboratories and identifies areas prone for improvement. A comprehensive online survey was distributed to all 21 Danish clinical biochemistry laboratories regarding their critical result management, including documentation practices, critical limit selection, and quality assurance measures. A total of 17 laboratories (81%) responded. The answers revealed a generally uniform approach to managing critical results, with all laboratories having 24-h reporting, local instructions and using the telephone as communication channel. However, variations were noted in documentation practices and critical limit selection. Notably, 23.5% of the laboratories reported that one out of every ten critical results was not reported, indicating a significant risk of delayed critical results. This is further complicated by the limited use of predefined timeframes for reporting and also, only few laboratories actively monitored response times. The findings emphasize the need for more standardized documentation and evaluation practices to align with international standards and to enhance patient safety. While the laboratories showed a commitment to standardized procedures, the study emphasizes the necessity of a National or Nordic guideline to supplement the ISO 15189:2022. This study is a step towards optimizing critical result management, not only in Danish clinical biochemistry laboratories but also across various laboratory specialties, thereby improving overall laboratory quality, efficiency, and patient safety.

Evaluation of Diagnostic Microbiology Capacity and Barriers in Testing for HIV and TB at Peripheral Hospital-Based Laboratories in Oyo-State, Nigeria.

The prevalence of tuberculosis (TB) and human immunodeficiency virus (HIV) coinfection in Nigeria is currently around 19.1%. This indicates that the two diseases are still a burden on the nation"s health. The aim of this study was to evaluate the diagnostic microbiology capacity and the barriers in performing assay for TB and HIV at peripheral district-level hospital-based laboratories in Oyo State, Nigeria. Diagnostic microbiology capacity was estimated using a scale of 100-point where scores ≤ 49% were categorized as low, 50-79% fair and ≥80% good. Barriers to diagnosis were summarized in proportions. The diagnostic microbiology capacity revealed that 6 (35.3%) and 11 (64.7%) of the laboratories had "fair" and "low" capacity, respectively, to detect TB in cerebrospinal fluid/sputum. In testing for HIV, 3 (17.6%) of the laboratories had "fair capacity" and 14 (82.4%) had "low capacity" to detect CD4 count and HIV antibodies in blood serum. The major diagnostic barriers in almost all (94.1%) the laboratories were lack of culture supplies and nonavailability of reagents/testing kits. There was no diagnostic microbiology service with good capacity to facilitate case detection of HIV and TB at the peripheral hospitals. Hence there is a need to improve the supply of reagents, culture stock and testing kits. This will facilitate the detection of TB and HIV cases in peripheral communities. IMPORTANCE This study provided a snapshot knowledge of testing capabilities and commodity availability at state laboratories. The findings should inform the action of stakeholders to improve diagnostic microbiology capacity, consequently enhancing diagnostic measures in detecting human immunodeficiency virus and Mycobacterium tuberculosis.

It is time for open access in clinical care.

A healthcare center widely sharing its internal guidelines on how to treat COVID-19 patients "just wasn't done." As the pandemic raged at a Boston hospital, the next generation of clinical leaders pushed for change.

Strengthening Antimicrobial Resistance Diagnostic Capacity in Rural Rwanda: A Feasibility Assessment.

Introduction: Antimicrobial resistance (AMR) is a global public health threat. Worse still, there is a paucity of data from low- and middle-income countries to inform rational antibiotic use. Objective: Assess the feasibility of setting up microbiology capacity for AMR testing and estimate the cost of setting up microbiology testing capacity at rural district hospitals in Rwanda. Methods: Laboratory needs assessments were conducted, and based on identified equipment gaps, appropriate requisitions were processed. Laboratory technicians were trained on microbiology testing processes and open wound samples were collected and cultured at the district hospital (DH) laboratories before being transported to the National Reference Laboratory (NRL) for bacterial identification and antibiotic susceptibility testing. Quality control (QC) assessments were performed at the DHs and NRL. We then estimated the cost of three scenarios for implementing a decentralized microbiology diagnostic testing system. Results: There was an eight-month delay from the completion of the laboratory needs assessments to the initiation of sample collection due to the regional unavailability of appropriate supplies and equipment. When comparing study samples processed by study laboratory technicians and QC samples processed by other laboratory staff, there was 85.0% test result concordance for samples testing at the DHs and 90.0% concordance at the NRL. The cost for essential equipment and supplies for the three DHs was $245,871. The estimated costs for processing 600 samples ranged from $29,500 to $92,590. Conclusion: There are major gaps in equipment and supply availability needed to conduct basic microbiology assays at rural DHs. Despite these challenges, we demonstrated that it is feasible to establish microbiological testing capacity in Rwandan DHs. Building microbiological testing capacity is essential for improving clinical care, informing rational antibiotics use, and ultimately, contributing to the establishment of robust national antimicrobial stewardship programs in rural Rwanda and comparable settings.

The rise in preanalytical errors during COVID-19 pandemic.

INTRODUCTION: The COVID-19 pandemic has posed several challenges to clinical laboratories across the globe. Amidst the outbreak, errors occurring in the preanalytical phase of sample collection, transport and processing, can further lead to undesirable clinical consequences. Thus, this study was designed with the following objectives: (i) to determine and compare the blood specimen rejection rate of a clinical laboratory and (ii) to characterise and compare the types of preanalytical errors between the pre-pandemic and the pandemic phases. MATERIALS AND METHODS: This retrospective study was carried out in a trauma-care hospital, presently converted to COVID-19 care centre. Data was collected from (i) pre-pandemic phase: 1st October 2019 to 23rd March 2020 and (ii) pandemic phase: 24th March to 31st October 2020. Blood specimen rejection rate was calculated as the proportion of blood collection tubes with preanalytical errors out of the total number received, expressed as percentage. RESULTS: Total of 107,716 blood specimens were screened of which 43,396 (40.3%) were received during the pandemic. The blood specimen rejection rate during the pandemic was significantly higher than the pre-pandemic phase (3.0% versus 1.1%; P < 0.001). Clotted samples were the commonest source of preanalytical errors in both phases. There was a significant increase in the improperly labelled samples (P < 0.001) and samples with insufficient volume (P < 0.001), whereas, a significant decline in samples with inadequate sample-anticoagulant ratio and haemolysed samples (P < 0.001). CONCLUSION: In the ongoing pandemic, preanalytical errors and resultant blood specimen rejection rate in the clinical laboratory have significantly increased due to changed logistics. The study highlights the need for corrective steps at various levels to reduce preanalytical errors in order to optimise patient care and resource utilisation.

Laboratory professionals' attitudes towards ISO 15189:2012 accreditation: an anonymous survey of three Croatian accredited medical laboratories.

INTRODUCTION: Effective implementation and continual compliance with ISO 15189:2012 require ongoing commitment and active involvement of laboratory staff. Our aim was to assess attitudes regarding accreditation implementation by conducting a survey in three Croatian accredited medical laboratories. MATERIALS AND METHODS: An anonymous survey consisting of 34 questions was distributed either electronically or in a paper form a week prior to scheduled annual audits. Distributions of answers regarding age, work experience, laboratory workplace, and education level and according to the respective laboratory were compared. RESULTS: The overall response rate was 76% (225/297). Preference towards working in an accredited laboratory and a positive attitude were revealed by 70% and 56% participants, respectively, with better process documentation as the main advantage. Only 14% of responders considered themselves completely familiar with ISO 15189:2012. Total of 68% of responders felt that accreditation increases the usual workload, with excessive paperwork as the main contributor. Half of the responders declared partial agreement that accreditation requirements and expectations were clearly explained and claimed that their suggestions were taken into account only occasionally, which was especially emphasized by technical staff. The vast majority (89%) completely follow the prescribed protocols. Only 27% consider turnaround time monitoring useful. Competence assessment is considered efficient by 41% of responders. The majority (73%) prefer an online audit in times of COVID-19. CONCLUSIONS: Despite an overall positive attitude towards accreditation, further efforts are needed in providing better education about ISO 15189:2012 for technical staff and modifying formats of competence assessment, in order to achieve better adherence to ISO 15189:2012 requirements.

An Initiative to Decrease Laboratory Testing in a NICU.

BACKGROUND AND OBJECTIVES: Laboratory testing is performed frequently in the NICU. Unnecessary tests can result in increased costs, blood loss, and pain, which can increase the risk of long-term growth and neurodevelopmental impairment. Our aim was to decrease routine screening laboratory testing in all infants admitted to our NICU by 20% over a 24-month period. METHODS: We designed and implemented a multifaceted quality improvement project using the Institute for Healthcare Improvement's Model for Improvement. Baseline data were reviewed and analyzed to prioritize order of interventions. The primary outcome measure was number of laboratory tests performed per 1000 patient days. Secondary outcome measures included number of blood glucose and serum bilirubin tests per 1000 patient days, blood volume removed per 1000 patient days, and cost. Extreme laboratory values were tracked and reviewed as balancing measures. Statistical process control charts were used to track measures over time. RESULTS: Over a 24-month period, we achieved a 26.8% decrease in laboratory tests performed per 1000 patient days (∽51 000 fewer tests). We observed significant decreases in all secondary measures, including a decrease of almost 8 L of blood drawn and a savings of $258 000. No extreme laboratory values were deemed attributable to the interventions. Improvement was sustained for an additional 7 months. CONCLUSIONS: Targeted interventions, including guideline development, dashboard creation and distribution, electronic medical record optimization, and expansion of noninvasive and point-of-care testing resulted in a significant and sustained reduction in laboratory testing without notable adverse effects.

Evolution of anatomic pathology workload from 2011 to 2019 assessed in a regional hospital laboratory via 574,093 pathology reports.

OBJECTIVE: Quantify changes in workload in relation to the anatomic pathologist workforce. METHODS: In house pathology reports for cytology and surgical specimens from a regional hospital laboratory over a nine- year period (2011-2019) were analyzed, using custom computer code. Report length for the diagnosis+microscopic+synoptic report, number of blocks, billing classification (L86x codes), billings, national workload model (L4E 2018), regional workload model (W2Q), case count, and pathologist workforce in full-time equivalents (FTEs) were quantified. Randomly selected cases (n = 1,100) were audited to assess accuracy. RESULTS: The study period had 574,093 pathology reports that could be analyzed. The coding accuracy was estimated at 95%. From 2011 to 2019: cases/year decreased 6% (66,056 to 61,962), blocks/year increased 20% (236,197 to 283,751), L4E workload units increased 23% (165,276 to 203,894), W2Q workload units increased 21% (149,841 to 181,321), report lines increased 19% (606,862 to 723,175), workforce increased 1% (30.42 to 30.77 FTEs), billings increased 13% ($6,766,927 to $7,677,109). W2Q in relation to L4E underweights work in practices with large specimens by up to a factor of 2x. CONCLUSIONS: Work by L4E for large specimens is underrated by W2Q. Reporting requirements and pathology work-up have increased workload per pathology case. Work overall has increased significantly without a commensurate workforce increase. The significant practice changes in the pathology work environment should prompt local investment in the anatomic pathology workforce.

Differential impacts of hemolysis on coagulation parameters of blood samples: A STROBE-compliant article.

ABSTRACT: This study aimed at investigating the impact of hemolysis on different coagulation parameters.A total of 216 venous blood samples without visible hemolysis were collected from adult patients at a tertiary referral center over six months. The plasma obtained was quantified for six coagulation parameters including prothrombin time, activated partial thromboplastin time, fibrinogen, D-dimer, antithrombin III, and protein C. The rest of the plasma from each blood sample was aliquoted into three tubes, each containing 1 mL of plasma with three different volumes of cell-free hemoglobin (i.e., 2, 4, 8 µL) from lysed RBCs to create simulated hemolyzed blood samples with hemoglobin concentration of approximately 0.1, 0.2, and 0.4 g/dL to mimic mild (1+), moderate (2+), and severe (3+) hemolysis, respectively, before repeating the coagulation tests to determine possible correlation between the simulated degree of hemolysis and the changes in test results of the coagulation parameters.Spearman correlation analysis showed significant decreases in the values of activated partial thromboplastin time, fibrinogen, D-dimer, and protein C values with an increasing degree of simulated hemolysis (all P < .01). Comparison of the percentage bias of biological variance showed significant positive associations of cell-free hemoglobin concentrations with the percentage bias of D-dimer and protein C. However, only the former was still within the range of biological variance under condition of simulated hemolysis. Besides, the presence of cell-free hemoglobin regardless of concentration had a notable impact on the percentage bias of activated partial thromboplastin time, whereas the influence was non-significant for prothrombin time, fibrinogen, and antithrombin III.The results showed different impacts of simulated hemolysis on six coagulation parameters, highlighting the dependence of clinical reliability on the coagulation parameter to be investigated in hemolytic blood samples.

Critical values in cytology.

The timely reporting of critical values, or values that may be life-threatening if immediate action is not taken, is essential to patient care and safety. Although some guidelines exist for critical diagnoses in cytology, not all laboratories have a specific list of diagnoses that should be considered critical, and the very existence of cytology "critical values" has been called into question. Here we propose a pragmatic system for determining cytology critical values and report our laboratory's critical value list, formulated based on a review of the medical literature regarding clinical urgency and other institutions' cytology critical value lists.

A model to establish autoverification in the clinical laboratory.

OBJECTIVES: Autoverification is the process of evaluating and validating laboratory results using predefined computer-based algorithms without human interaction. By using autoverification, all reports are validated according to the standard evaluation criteria with predefined rules, and the number of reports per laboratory specialist is reduced. However, creating and validating these rules are the most demanding steps for setting up an autoverification system. In this study, we aimed to develop a model for helping users establish autoverification rules and evaluate their validity and performance. DESIGN & METHODS: The proposed model was established by analyzing white papers, previous study results, and national/international guidelines. An autoverification software (myODS) was developed to create rules according to the model and to evaluate the rules and autoverification rates. The simulation results that were produced by the software were used to demonstrate that the determined framework works as expected. Both autoverification rates and step-based evaluations were performed using actual patient results. Two algorithms defined according to delta check usage (Algorithm A and B) and three review limits were used for the evaluation. RESULTS: Six hundred seventeen rules were created according to the proposed model. 1,976 simulation results were created for validation. Our results showed that manual review limits are the most critical step in determining the autoverification rate, and delta check evaluation is especially important for evaluating inpatients. Algorithm B, which includes consecutive delta check evaluation, had higher AV rates. CONCLUSIONS: Systemic rule formation is a critical factor for successful AV. Our proposed model can help laboratories establish and evaluate autoverification systems. Rules created according to this model could be used as a starting point for different test groups.

Incidents in Molecular Pathology: Frequency and Causes During Routine Testing.

CONTEXT.­: Errors in laboratory medicine could compromise patient safety. Good laboratory practice includes identifying and managing nonconformities in the total test process. Varying error percentages have been described in other fields but are lacking for molecular oncology. OBJECTIVES.­: To gain insight into incident causes and frequency in the total test process from 8 European institutes routinely performing biomarker tests in non-small cell lung cancer and colorectal cancer. DESIGN.­: All incidents documented in 2018 were collected from all hospital services for pre-preanalytical entries before the biomarker test, as well as specific incidents for biomarker tests. RESULTS.­: There were 5185 incidents collected, of which 4363 (84.1%) occurred in the pre-preanalytical phase (all hospital services), 2796 of 4363 (64.1%) related to missing or incorrect request form information. From the other 822 specific incidents, 166 (20.2%) were recorded in the preanalytical phase, 275 (33.5%) in the analytical phase, and 194 (23.6%) in the postanalytical phase, mainly due to incorrect report content. Only 47 of 822 (5.7%) incidents were recorded in the post-postanalytical phase, and 123 (15.0%) in the complete total test process. For 17 of 822 (2.1%) incidents the time point was unknown. Pre-preanalytical incidents were resolved sooner than incidents on the complete process (mean 6 versus 60 days). For 1215 of 5168 (23.5%) incidents with known causes a specific action was undertaken besides documenting them, not limited to accredited institutes. CONCLUSIONS.­: There was a large variety in the number and extent of documented incidents. Correct and complete information on the request forms and final reports are highly error prone and require additional focus.

Impact of the COVID-19 pandemic on cytology practice: An international survey in the Asia-Pacific region.

BACKGROUND: The purpose of the current study was to examine the impact of coronavirus disease 2019 (COVID-19) on various aspects of cytology practice in the Asia-Pacific region. METHODS: An online questionnaire was distributed to cytopathology laboratories in 24 Asia-Pacific countries to explore the impact of restrictive measures on access to health care, use of general and personal protective equipment (PPE), and changes in cytology workflow and workload from February to April 2020. RESULTS: A total of 167 cytopathology laboratories from 24 countries responded to the survey; the majority reported that restrictive measures that limited the accessibility of health care services had been implemented in their cities and/or countries (80.8%) and their hospitals (83.8%). The respondents noted that COVID-19 had an impact on the cytologic workflow as well as the workload. Approximately one-half of the participants reported the implementation of new biosafety protocols (54.5%) as well as improvements in laboratory facilities (47.3%). Rearrangement or redeployment of the workforce was reported in 53.3% and 34.1% of laboratories, respectively. The majority of the respondents reported a significant reduction (>10%) in caseload associated with both gynecological (82.0%) and nongynecological specimens (78.4%). Most laboratories reported no significant change in the malignancy rates of both gynecological (67.7%) and nongynecological specimens (58.7%) compared with the same period in 2019. CONCLUSIONS: The results of the survey demonstrated that the COVID-19 pandemic resulted in a significant reduction in the number of cytology specimens examined along with the need to implement new biosafety protocols. These findings underscore the need for the worldwide standardization of biosafety protocols and cytology practice.

Strategies for Successful Catheterization Laboratory Recovery From the COVID-19 Pandemic.

As the world slowly starts to recover from the coronavirus disease-2019 pandemic, health care systems are now thinking about resuming elective cardiovascular procedures, including procedures in cardiac catheterization laboratories. Rebooting catheterization laboratories will be an arduous process, in part because of limited health care resources, new processes, and fears stemming from the coronavirus disease-2019 pandemic. The authors propose a detailed phased-in approach that considers clinical, patient-centered, and operational strategies to safely and effectively reboot catheterization laboratory programs during these unprecedented times. This model balances the delivery of essential cardiovascular care with reduced exposure and preservation of resources. The guiding principles detailed in this review can be used by catheterization laboratory programs when restarting elective interventional procedures.

Description of a new biosafe procedure for cytological specimens from patients with COVID-19 processed by liquid-based preparations.

BACKGROUND: Coronavirus disease 2019 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and represents the causative agent of a potentially fatal disease. The spread of the infection and the severe clinical disease have led to the widespread adoption of social distancing measures. Special attention and efforts to protect or reduce transmission have been applied at all social levels, including health care operators. Hence, this reports focuses on the description of a new protocol for the safe management of cytological samples processed by liquid-based cytology (LBC) with an evaluation of the changes in terms of morphology and immunoreactivity. METHODS: From March 11 to April 25, 2020, 414 cytological cases suspicious for SARS-CoV-2 were processed with a new virus-inactivating method suggested by Hologic, Inc, for all LBC specimens. RESULTS: The samples showed an increased amount of fibrin in the background. A slight decrease in cellular size was also observed in comparison with the standard method of preparation. Nonetheless, the nuclear details of the neoplastic cells were well identified, and the immunoreactivity of the majority of those cells was maintained. The cell blocks did not show significant differences in morphology, immunoreactivity, or nucleic acid stability. CONCLUSIONS: Despite some minor changes in the morphology of the cells, the results of this study highlight that the adoption of the new protocol for the biosafety of LBC-processed samples in pathology laboratories is important for minimizing the risk for personnel, trainees, and cytopathologists without impairing the diagnostic efficacy of the technique.

Costs analysis of a training intervention for the reduction of preanalytical errors in primary care samples.

BACKGROUND: To perform a cost-error analysis based on a quasi-experimental pre-post study of the preanalytical errors in 2 hospital laboratories. The real cost and theoretical cost are defined as the cost resulting from errors with or without the training intervention. The real impact associated to the training program was estimated, calculated as the total associated to the preanalytical errors cost difference. The costs were measured using Andalusian Public Health Service fees. Cost analysis of an educational intervention presented in a previous study from 2017. Preanalytical errors were detected in the laboratories of the University Hospital Virgen de la Victoria (Málaga, Spain) and in the University Hospital Juan Ramón Jiménez (Huelva, Spain). METHODS: The founded errors were divided into blood and urine samples. Univariate sensitivity analysis was used to assess how parameter uncertainty impacted on overall results. Variations of parameters between 0% and 5% were substituted into the base case. RESULTS: The real impact associated with educational intervention in LAB1 was an increase of &OV0556;16,961.378, and the expected impact was an increase &OV0556;78,745.27 (difference of &OV0556;61,783.9). In LAB2, the real impact in the same period amounted to &OV0556;260,195.37, and the expected impact was &OV0556;193,905.83 (difference of -&OV0556;66,289.54). The results were different in the 2 laboratories, proving the intervention in only one of them to be more effective. CONCLUSIONS: Costs analysis determined that this training intervention can provide saves in the costs, as the effectiveness of the educational sessions in reducing preanalytical errors currently results in a significant decrease of the costs associated with these errors.

A Feasible Laboratory-Strengthening Intervention Yielding a Sustainable Clinical Bacteriology Sector to Support Antimicrobial Stewardship in a Large Referral Hospital in Ethiopia.

Background: Access to clinical bacteriology in low resource settings (LRS) is a key bottleneck preventing individual patient management of treatable severe infections, detection of antimicrobial resistance (AMR), and implementation of effective stewardship interventions. We sought to demonstrate the feasibility of a practical bundle of interventions aimed at implementing sustainable clinical bacteriology services at Tikur Anbessa Specialized Hospital in Addis Ababa, Ethiopia, and report on cost and intensity of supervision. Methods: Starting in Dec 2015, an intervention based on the CLSI QMS01-A guideline was established, consisting of (i) an initial needs assessment, (ii) development of key standard operating procedures, (iii) adaptation of processes for LRS, (iv) training and supervision of laboratory staff via consultant visits and existing online resources, and (v) implementation of a practical quality systems approach. A guiding principle of the bundle was sustainability of all interventions post implementation. Outcomes and challenges: An initial investment of ~US$ 26,200 for laboratory reagents, and a total of 50 visit-days per year from three Canadian and Norwegian microbiologists were committed. Twelve SOPs, including antimicrobial susceptibility testing, were adapted, and an automated blood culture platform was donated (bioMerieux). In the first 18 months of implementation of the intervention, the average volume of specimens analyzed in the lab went from 15/day to 75/day. The number of blood cultures tested increased from an average of 2/day to over 45/day. Antimicrobial susceptibility testing was introduced and cumulative antibiograms were generated for the institution. Quality control was implemented for all procedures and quality assurance tools implemented included external quality assurance and proficiency testing of six technologists with longitudinal follow-up. The laboratory is on the path toward SLIPTA accreditation by the African Society for Laboratory Medicine. Reagent costs, staff training and retention, and engagement of clinical personnel with the lab proved to be manageable challenges. Key external challenges include in-country supply-chain management issues, lack of competition among distributors, and foreign-currency exchange distortions. Conclusions: Using a relatively low-intensity intervention based on existing training tools and accreditation schemes, we demonstrate that establishment of reasonable-quality clinical bacteriology is not only within reach but also a critical step toward assessing the burden of AMR in settings like this one and implementing effective stewardship strategies.

International Council for Standardization in Haematology (ICSH) recommendations for laboratory measurement of ADAMTS13.

This guidance document was prepared on behalf of the International Council for Standardization in Haematology (ICSH), by the ADAMTS13 Assay Working Group, which comprises an international group of both clinical and laboratory experts. The document provides recommendations on best practice for the performance of ADAMTS13 assays in clinical laboratories. ADAMTS13 assays support the differential diagnosis of thrombotic microangiopathies and have utility in the management of thrombotic thrombocytopenic purpura (TTP). There are three types of assay: activity, antigen and autoantibody/inhibitor assays. Methods for activity assays differ in terms of sensitivity, specificity, precision and turnaround time. The most widely used assays involve VWF peptide substrates and either chromogenic ELISA or FRET techniques, although chemiluminescence assays and rapid screening tests have recently become available. Tests for autoantibodies and inhibitors allow confirmation of acquired, immune-mediated TTP, while antigen assays may be useful in congenital TTP and as prognostic markers. In this document, we have attempted to describe ADAMTS13 assays and the conditions that affect them, as well as: blood collection, sample processing, quality control, standardization and clinical utility; recognizing that laboratories in different parts of the world have varying levels of sophistication. The recommendations are based on expert opinion, published literature and good clinical laboratory practice.