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Laboratory Performance (laboratory + performance)
Selected AbstractsAssessing immunophenotyping performance: Proficiency-validation for adopting improved flow cytometry methodsCYTOMETRY, Issue 4 2007Lance E. Hultin Abstract Background: The continuous improvement and evolution of immune cell phenotyping requires periodic upgrading of laboratory methods and technology. Flow cytometry laboratories that are participating in research protocols sponsored by the NIAID are required to perform "switch" studies to validate performance before methods for T-cell subset analysis can be changed. Methods: Switch studies were conducted among the four flow cytometry laboratories of the Multicenter AIDS Cohort Study (MACS), comparing a 2-color, lyse-wash method and a newer, 3-color, lyse no-wash method. Two of the laboratories twice failed to satisfy the criteria for acceptable differences from the previous method. Rather than repeating more switch studies, these laboratories were allowed to adopt the 3-color, lyse no-wash method. To evaluate the impact of the switch to the new method at these two sites, their results with the new method were evaluated within the context of all laboratories participating in the NIH-NIAID-Division of AIDS Immunology Quality Assurance (IQA) proficiency-testing program. Results: Laboratory performance at these two sites substantially improved relative to the IQA standard test results. Variation across the four MACS sites and across replicate samples was also reduced. Conclusions: Although switch studies are the conventional method for assessing comparability of laboratory methods, two alternatives to the requirement of repeating failed switch studies should be considered: (1) test the new method and assess performance on the proficiency testing reference panel, and (2) prior to adoption of the new methods, use both the old and the new method on the reference panel samples and demonstrate that performance with the new method is better according to standard statistical procedures. These alternatives may help some laboratories' transition to a new and superior methodology more quickly than if they are required to attempt multiple, serial switch studies. © 2007 Clinical Cytometry Society [source] Quality control of CD4+ T-lymphocyte enumeration: Results from the last 9 years of the United Kingdom national external quality assessment scheme for immune monitoring (1993,2001)CYTOMETRY, Issue 2 2002Liam Whitby Abstract The human immunodeficiency virus (HIV) global epidemic has necessitated the routine enumeration of T-lymphocyte subsets, which has created a need for external quality assurance (EQA). The United Kingdom National External Quality Assessment Scheme (UK NEQAS) for Immune Monitoring provides EQA for 296 laboratories in 40 countries. In 1993, UK NEQAS developed and incorporated into its program stabilized whole blood that enables the accurate monitoring of laboratory performance. Overall, the mean interlaboratory coefficient of variation (CV) for percentage CD4+ T-lymphocyte subset enumeration has fallen from 15% to less than 5%, as a direct result of the increased use of CD45/ side scatter (SSC) gating. Laboratories using alternative gating strategies (i.e., CD45/CD14 or forward scatter [FSC]/SSC) were about 7.4 times more likely to fail an EQA exercise. Furthermore, the adoption of single-platform technology resulted in a reduction of the overall mean interlaboratory CV for absolute CD4+ T lymphocytes from 56% (prior to the widespread use of single-platform technology) to 9.7%. Individual laboratory deficiencies were also identified using a performance monitoring system and, through re-education by collaboration with the coordinating center, satisfactorily resolved. In conclusion, during the last 9 years, the UK NEQAS for Immune Monitoring program has highlighted the significant technological advances made by laboratories worldwide that undertake lymphocyte subset enumeration. Cytometry (Clin. Cytometry) 50:102,110, 2002. © 2002 Wiley-Liss, Inc. [source] Laboratory identification of factor VIII inhibitors in the real world: the experience from AustralasiaHAEMOPHILIA, Issue 4 2010E. J. FAVALORO Summary., The laboratory has a key role in the initial detection of factor inhibitors and an ongoing role in the measurement of inhibitor titres during the course of inhibitor eradication therapy. The most commonly seen factor inhibitors are those directed against factor VIII (FVIII), usually detected either using the original or Nijmegen-modified Bethesda assay. In view of previously demonstrated high variability in laboratory results for inhibitor assays, we have more extensively examined laboratory performance in the identification of FVIII inhibitors. Over the past 3 years, we conducted two questionnaire-based surveys and two wet-challenge surveys utilizing eight samples comprising no FVIII inhibitor (n = 1), or low-titre (n = 2), medium-titre (n = 3) or high-titre (n = 2) FVIII inhibitor. Four samples were tested by 42 laboratories in 2007, and four by 52 laboratories in 2009. High inter-laboratory variation was evident, with CVs around 50% not uncommon, and some 10% of all laboratories (or around 15% of laboratories using Bethesda method) failed to detect low-level inhibitors of around 1 BU mL,1. Laboratories using the Nijmegen method appeared to perform better than those using a standard Bethesda assay, with lower evident assay variation and no false negatives. There was a wide variety of laboratory practice, with no two laboratories using exactly the same process for testing and interpretation of factor inhibitor findings. In conclusion, our study indicates that there is still much need for standardization and improvement in factor inhibitor detection, and we hope that our findings provide a basis for future improvements in this area. [source] A placebo controlled investigation into the effects of paroxetine and mirtazapine on measures related to car driving performanceHUMAN PSYCHOPHARMACOLOGY: CLINICAL AND EXPERIMENTAL, Issue 4 2003F. Ridout Abstract Objective To assess the effects of paroxetine and mirtazapine on psychometric performance related to car driving, including an on-the-road test of BRT. Method In a 4-way, double blind randomised crossover study, 12 healthy volunteers received paroxetine 20,mg mane, mirtazapine 15,mg/30,mg nocte (comparator), mirtazapine 15,mg mane/15,mg b.i.d.(verum) and placebo over a 5 day period with a washout period of 7 days between treatments. Psychometric assessments included ,on-the-road' BRT (BRT), CFF (CFF), CRT (CRT) and subjective measures of sedation and sleep parameters. Results Paroxetine had no significant effect on BRT compared with placebo. Although subjective ratings of sleep quality and sedation were impaired, there were significant improvements in both CFF and the recognition reaction component of CRT with paroxetine. Mirtazapine 15,mg/30,mg nocte impaired laboratory performance and some subjective tests. Mirtazapine 15 mg mane/15,mg b.i.d. improved sleep, but significantly impaired all other measures. Conclusion Paroxetine 20,mg/day has no psychomotor or behavioural toxicity and has no negative impact on BRT. Further research into the chronic and sub-chronic effects of mirtazapine is needed to establish the clinical significance of these results. Copyright © 2003 John Wiley & Sons, Ltd. [source] EQAS for peripheral blood morphology in Spain: a 6-year experienceINTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 6 2008G. GUTIÉRREZ Summary The Spanish haematology external quality assessment scheme (EQAS), established in 1984, is run by the Spanish Haematology and Haemotherapy Association (AEHH) [Quality Assurance in Health Care 3 (1991) 75] and functions to evaluate the quality and reproducibility of the assessment of diagnostic samples by clinical laboratories. The Hospital Clinic of the University of Barcelona (HCB) serves as the EQAS Coordination Centre and follows the guidelines established by the International Committee for Standardization in Haematology [Annali dell'Istituto superiore di Sanità 31 (1995) 95; International Journal of Hematology 68 (1998) 45]. During the period 2001,2006, replicates of 25 different blood films were sent to 604 EQAS participants for cell morphology evaluation. Some patient details corresponding to the samples were disclosed, such us age, sex, haemoglobin value and white blood cell count. The participants were asked to select up to four significant morphology features using a coding list, provided by the Coordination Centre, which included significant morphological alterations that appear in haematopoietic cells. For each survey, individual results were assessed against the morphological reference results (MRR) established by the Cytology Group of the AEHH (,true' answers). This paper describes the organization of the 6-year-long study and the evaluation of laboratory performance for blood smear interpretation by the Spanish haematology EQAS. Different performance levels were detected relative to the laboratory category. Laboratories providing services to hospitalized patients showed higher performances compared with laboratories providing services to nonhospitalized patients. Pathological lymphoid cells were the most difficult to identify by the participants. To improve the results in EQAS peripheral blood morphology, the development of specific cytology educational trainings is discussed. [source] Repeated HIV-1 resistance genotyping external quality assessments improve virology laboratory performance,JOURNAL OF MEDICAL VIROLOGY, Issue 2 2006Diane Descamps Abstract The performance of French virology laboratories belonging to the ANRS network has been assessed annually for 3 years. The performance of these laboratories was compared between the years 2002 and 2003. Ten and 7 coded samples were sent to 38 virology laboratories in 2002 and 45 virology laboratories in 2003, respectively. Each panel of coded samples included at least one HIV-negative control, a pair of duplicate specimens, samples with a wide range of viral loads, and samples with a large number of resistance mutations. The laboratories used their standard sequencing procedures and were asked to report the amino acids at codons associated with resistance mutations, based on the IAS-USA expert panel list. The reference amino acid sequences were defined as those most frequently reported by the participants. The specificity of detection of RT mutations was significantly better in 2003 (99.9%) than in 2002 (99.7%) (P,=,0.05). There was no difference between 2002 and 2003 in the specificity of detection of protease mutations (99.6% and 99.8%) or the sensitivity of detection of RT mutations (98.8% and 98.2%). The sensitivity of detection of protease mutations improved significantly between 2002 and 2003 (97.6% and 99.0%, respectively; P,=,0.037). The proportion of laboratories reporting fully accurate results, in terms of amplification, specificity, sensitivity, and reproducibility, tended to increase between 2002 and 2003 (P,=,0.077). No errors were made by 19% of laboratories in 2002, compared to 42% in 2003. These results show the value of repeated external quality assessments. J. Med. Virol. 78:153,160, 2006. © 2005 Wiley-Liss, Inc. [source] Summary findings of the fourth international radiocarbon intercomparison (FIRI)(1998,2001)JOURNAL OF QUATERNARY SCIENCE, Issue 7 2002Elisabetta Boaretto Abstract Interlaboratory comparisons have been widely used in applied radiocarbon science. These are an important part of ongoing quality assurance (QA) programmes, which are vital to the appropriate interpretation of the evidence provided by the 14C record in Quaternary applications (including climate change and environmental reconstruction). International comparisons of laboratory performance are an essential component of the quality assurance process in radiocarbon dating. If the user community is to have confidence in radiocarbon results, it needs to be assured that laboratories world wide are producing measurements that are reliable and in accordance with ,good practice'. The findings from the most recent (completed in 2001) and extensive (more than 90 participating laboratories) radiocarbon intercomparison (FIRI) are reported here. This study was designed (i) to assess comparability, or otherwise, of the results from different laboratories and (ii) to quantify the extent and possible causes of any interlaboratory variation. The results demonstrate that there are no significant differences amongst the main measurement techniques (gas proportional counting, liquid scintillation counting and accelerator mass spectrometry (AMS)) but there is evidence of small laboratory offsets relative to known age samples for some laboratories. There is also evidence in some cases of underestimation of measurement precision. Approximately 10% of all results were classified as extreme (outliers) and these results were generated by 14% of the laboratories. Overall, the evidence supports the fact that radiocarbon laboratories are generally accurate and precise but that, notwithstanding internal QA procedures, some problems still occur, which can best be detected by participation in independent intercomparisons such as FIRI, where the results allow individual laboratories to assess their performance and to take remedial measures where necessary. The results from FIRI are significant in that they show a broad measure of agreement between measurements made in different laboratories on a wide range of materials and they also demonstrate no statistically significant difference between measurements made by radiometric or AMS techniques. Copyright © 2002 John Wiley & Sons, Ltd. [source] Organisation of proficiency testing for plant health diagnostic tests: the experience of FAPAS®EPPO BULLETIN, Issue 1 2010A. Reynolds Proficiency testing (PT) is an established quality assurance measure and is based on the comparison of laboratories' results in an inter-laboratory trial. It highlights problems in laboratory analysis and is an educational tool to help improve data quality. This article describes how PT is organised by FAPAS®. FAPAS® is an international PT provider (external quality assessments) for food chemistry, food microbiology, genetically modified material and water/environmental samples. Since 2007, FAPAS® have organized plant health proficiency tests in conjunction with the Plant Pest and Disease Identification Programme at the Food and Environment Research Agency (Fera). Up until 2009, FAPAS® has organised seven plant health proficiency tests that covered the identification of lyophilised bacteria, viruses in leaves and fungi in agar plugs. In 2009, FAPAS® organized over 10 plant health proficiency tests under the banner of ,PhytoPAS', including Potato spindle tuber viroid, Phytophthora ramorum, Thrips palmi, Erwinia amylovora, Clavibacter michiganensis subsp. sepedonicus, etc. DNA extracts, cyst nematodes (Globodera pallida) and slides/immunofluorescence (IF) slides have been added to the programme. The organization of the plant health proficiency tests follows a similar pattern. Suitable test materials are prepared and tested for quality before distribution to requesting participants. Laboratories usually have 1,2 months to analyze their samples and return their results. A report is then compiled for issue to laboratories and these contain all results in an anonymous form, so that laboratories can compare their results with those of other participants. If a laboratory's performance is unsatisfactory then it is up to them to investigate the situation. Thus, the primary purpose of PT is the detection of inaccuracy in a laboratory's results, so that they can investigate the problems and initiate corrective procedures. [source] | |||||||||||||