Survey material choices in haematology EQA: a confounding factor in automated counting performance assessment

The complete blood count (CBC) is one of the most frequently requested tests in laboratory medicine, performed in a range of healthcare situations. The provision of an ideal assay material for external quality assessment is confounded by the fragility of the cellular components of blood, the lack of commutability of stabilised whole blood material and the lack of certified reference materials and methods to which CBC results can be traced. The choice of assay material between fresh blood, extended life assay material and fully stabilised, commercially prepared, whole blood material depends upon the scope and objectives of the EQA scheme. The introduction of new technologies in blood counting and the wider clinical application of parameters from the extended CBC will bring additional challenges for the EQA provider

The development of performance assessment tools to improve the quality of diagnosis and monitoring of haemoglobinopathy disorders

The haemoglobinopathies are complex inherited disorders of haemoglobin synthesis. Although carriers are generally asymptomatic, homozygous or compound heterozygous inheritance of globin gene mutations may result in severe conditions, identified as a major burden of disease worldwide. The main means of control of the conditions is by carrier screening using specialist laboratory testing, allowing individuals an informed reproductive choice. UK NEQAS Haematology provides a comprehensive external quality assessment service for the haemoglobinopathies and is in a unique position to provide an overview of laboratory performance. The increased emphasis on laboratory quality and a shift in the profile of the participating laboratories from mainly UK-based to more than half non-British Isles in the past decade are drivers for continued improvement in performance assessment methods. The project looked at aspects of performance of both UK NEQAS and the participants. A review of historical quantitation data for haemoglobin (Hb) A2, the standard biomarker for beta thalassaemia carrier identification, showed there remains a need for standardisation between methods of analysis. The survey material distributed for testing was examined to exclude commutability and stability as confounding factors in performance assessment. Changes to Hb A2 performance scoring have been suggested including the identification of one-off analytical EQA errors that could represent misdiagnosis of a beta thalassaemia carrier. In newborn screening, a difference was seen in the sensitivity of different analysers at the low levels of adult haemoglobin (Hb A) seen in a newborn infant with homozygous beta thalassaemia. A significant difference in performance in result interpretation was seen between English NHS laboratories and those outside the British Isles. The scheme should extend performance management in interpretation to all laboratories including the non-British Isles group, to ensure that the scheme remains credible to participants and fulfils its remit to improve performance wherever patients are tested. This will however require the scheme to develop the EQA data capture methods better to reflect current laboratory practice

Special issue on External Quality Assessment in Laboratory Medicine – current challenges and future trends

Quality assurance in the modern clinical laboratory is evidenced through the complementary process-es of internal quality control and external quality assessment, also known as proficiency testing. By these processes and the achievement of accreditation to international (e.g. ISO) standards, the labor-atory is able to demonstrate its competence to the users of its services, i.e. the clinicians and the pa-tients they care for, who have an expectation that the results of diagnostic testing and monitoring of treatment are correct, comparable and fit-for-purpose within the scope of the service, wherever they are performed

EMQN best practice guidelines for molecular and haematology methods for carrier identification and prenatal diagnosis of the haemoglobinopathies

Haemoglobinopathies constitute the commonest recessive monogenic disorders worldwide, and the treatment of affected individuals presents a substantial global disease burden. Carrier identification and prenatal diagnosis represent valuable procedures that identify couples at risk for having affected children, so that they can be offered options to have healthy offspring. Molecular diagnosis facilitates prenatal diagnosis and definitive diagnosis of carriers and patients (especially ‘atypical’ cases who often have complex genotype interactions). However, the haemoglobin disorders are unique among all genetic diseases in that identification of carriers is preferable by haematological (biochemical) tests rather than DNA analysis. These Best Practice guidelines offer an overview of recommended strategies and methods for carrier identification and prenatal diagnosis of haemoglobinopathies, and emphasize the importance of appropriately applying and interpreting haematological tests in supporting the optimum application and evaluation of globin gene DNA analysis

IL-15 trans-presentation promotes human NK cell development and differentiation in vivo

The in vivo requirements for human natural killer (NK) cell development and differentiation into cytotoxic effectors expressing inhibitory receptors for self–major histocompatability complex class I (MHC-I; killer Ig-like receptors [KIRs]) remain undefined. Here, we dissect the role of interleukin (IL)-15 in human NK cell development using Rag2−/−γc−/− mice transplanted with human hematopoietic stem cells. Human NK cell reconstitution was intrinsically low in this model because of the poor reactivity to mouse IL-15. Although exogenous human IL-15 (hIL-15) alone made little improvement, IL-15 coupled to IL-15 receptor α (IL-15Rα) significantly augmented human NK cells. IL-15–IL-15Rα complexes induced extensive NK cell proliferation and differentiation, resulting in accumulation of CD16+KIR+ NK cells, which was not uniquely dependent on enhanced survival or preferential responsiveness of this subset to IL-15. Human NK cell differentiation in vivo required hIL-15 and progressed in a linear fashion from CD56hiCD16−KIR− to CD56loCD16+KIR−, and finally to CD56loCD16+KIR+. These data provide the first evidence that IL-15 trans-presentation regulates human NK cell homeostasis. Use of hIL-15 receptor agonists generates a robust humanized immune system model to study human NK cells in vivo. IL-15 receptor agonists may provide therapeutic tools to improve NK cell reconstitution after bone marrow transplants, enhance graft versus leukemia effects, and increase the pool of IL-15–responsive cells during immunotherapy strategies

Do We Know Why We Make Errors in Morphological Diagnosis? An Analysis of Approach and Decision-Making in Haematological Morphology

Background: The laboratory interpretation of blood film morphology is frequently a rapid, accurate, and cost-effective final-stage of blood count analysis. However, the interpretation of findings often rests with a single individual, and errors can carry significant impact. Cell identification and classification skills are well supported by existing resources, but the contribution and importance of other skills are less well understood. Methods: The UK external quality assurance group in haematology (UK NEQAS(H)) runs a Continued Professional Development scheme where large digital-images of abnormal blood smears are presented using a web-based virtual microscope. Each case is answered by more than 800 individuals. Morphological feature selection and prioritisation, as well as diagnosis and proposed action, are recorded. We analysed the responses of participants, aiming to identify successful strategies as well as sources of error. Findings: The approach to assessment by participants depended on the affected cell type, case complexity or skills of the morphologist. For cases with few morphological abnormalities, we found that accurate cell identification and classification were the principle requirements for success. For more complex films however, feature recognition and prioritisation had primary importance. Additionally however, we found that participants employed a range of heuristic techniques to support their assessment, leading to associated bias and error. Interpretation: A wide range of skills together allow successful morphological assessment and the complexity of this process is not always understood or recognised. Heuristic techniques are widely employed to support or reinforce primary observations and to simplify complex findings. These approaches are effective and are integral to assessment; however they may also be a source of bias or error. Improving outcomes and supporting diagnosis require the development of decision-support mechanisms that identify and support the benefits of heuristic strategies while identifying or avoiding associated biases. Funding: The CPD scheme is funded by participant subscription

Laboratory diagnosis of the rare anaemias: external quality assessment benefits patient care

Since its introduction in the 1960s, external quality assessment has developed to become an essential component of the quality management system of the diagnostic laboratory. External quality assessment provides a long term, retrospective view of laboratory performance, demonstrating the competence of the laboratory to others. The ENERCA project (the European Network for Rare and Congenital Anaemias) has established a list of core laboratory tests that are used in the diagnosis of rare and congenital anaemias, which has been used as the basis for questionnaires to laboratories, to establish the use and quality assurance of diagnostic testing in the congenital and rare anaemias, and to European EQA providers for services in this key area. In general, the provision of EQA for rare and congenital anaemias is widely variable with little provision for the very rare disorders. For the more common congenital anaemias, such as the haemoglobinopathies and thalassaemias, provision is better but there is variation in aspects of the scheme design, especially the frequency of distribution. Where laboratories did not take part in EQA for individual tests, or there was no EQA available, a desire to participate was expressed in 66% (102/154) of cases. The provision of external quality assessment (EQA) services for rare disorders is a challenge. For many of these conditions, the number of patients in any one member state is very small with only a few laboratories providing diagnostic testing. In these cases, the development of pan-European or cross-border EQA may be the only means by which standardisation of methods and results can be achieved. An EQA survey of 243 laboratories for performance in Hb A2 quantification showed encouraging results in that there was a clear differentiation in the results from a beta Thalassaemia carrier and an individual with no evidence of Thalassaemia; however, a bias was observed between different methods of measurement

Vanishing Immunoglobulins: The Formation of Pauci-Immune Lesions in Myeloperoxidase-Antineutrophil Cytoplasmic Antibody-Associated Vasculitis

Background: Morphological examination of blood films remains the reference standard for malaria diagnosis. Supporting the skills required to make an accurate morphological diagnosis is therefore essential. However, providing support across different countries and environments is a substantial challenge. Objective: This paper reports a scheme supplying digital slides of malaria-infected blood within an Internet-based virtual microscope environment to users with different access to training and computing facilities. The feasibility of the approach was established, allowing users to test, record, and compare their own performance with that of other users. Methods: From Giemsa stained thick and thin blood films, 56 large high-resolution digital slides were prepared, using high-quality image capture and 63x oil-immersion objective lens. The individual images were combined using the photomerge function of Adobe Photoshop and then adjusted to ensure resolution and reproduction of essential diagnostic features. Web delivery employed the Digital Slidebox platform allowing digital microscope viewing facilities and image annotation with data gathering from participants. Results: Engagement was high with images viewed by 38 participants in five countries in a range of environments and a mean completion rate of 42/56 cases. The rate of parasite detection was 78% and accuracy of species identification was 53%, which was comparable with results of similar studies using glass slides. Data collection allowed users to compare performance with other users over time or for each individual case. Conclusions: Overall, these results demonstrate that users worldwide can effectively engage with the system in a range of environments, with the potential to enhance personal performance through education, external quality assessment, and personal professional development, especially in regions where educational resources are difficult to access