External Quality Assurance Testing Research Articles

Gamma-Glutamyl Transferase (GGT) Is the Leading External Quality Assurance Predictor of ISO15189 Compliance for Pathology Laboratories.

Pathology results are central to modern medical practice, informing diagnosis and patient management. To ensure high standards from pathology laboratories, regulators require compliance with international and local standards. In Australia, the monitoring and regulation of medical laboratories are achieved by conformance to ISO15189-National Pathology Accreditation Advisory Council standards, as assessed by the National Association of Testing Authorities (NATA), and an external quality assurance (EQA) assessment via the Royal College of Pathologists of Australasia Quality Assurance Program (RCPAQAP). While effective individually, integration of data collected by NATA and EQA testing promises advantages for the early detection of technical or management problems in the laboratory, and enhanced ongoing quality assessment. Random forest (RF) machine learning (ML) previously identified gamma-glutamyl transferase (GGT) as a leading predictor of NATA compliance condition reporting. In addition to further RF investigations, this study also deployed single decision trees and support vector machines (SVM) models that included creatinine, electrolytes and liver function test (LFT) EQA results. Across all analyses, GGT was consistently the top-ranked predictor variable, validating previous observations from Australian laboratories. SVM revealed broad patterns of predictive EQA marker interactions with NATA outcomes, and the distribution of GGT relative deviation suggested patterns by which to identify other strong EQA predictors of NATA outcomes. An integrated model of pathology quality assessment was successfully developed, via the prediction of NATA outcomes by EQA results. GGT consistently ranked as the best predictor variable, identified by combining recursive partitioning and SVM ML strategies.

Comprehensive investigation of sources of misclassification errors in routine HIV testing in Zimbabwe.

IntroductionMisclassification errors have been reported in rapid diagnostic HIV tests (RDTs) in sub‐Saharan African countries. These errors can lead to missed opportunities for prevention‐of‐mother‐to‐child‐transmission (PMTCT), early infant diagnosis and adult HIV‐prevention, unnecessary lifelong antiretroviral treatment (ART) and wasted resources. Few national estimates or systematic quantifications of sources of errors have been produced. We conducted a comprehensive assessment of possible sources of misclassification errors in routine HIV testing in Zimbabwe.MethodsRDT‐based HIV test results were extracted from routine PMTCT programme records at 62 sites during national antenatal HIV surveillance in 2017. Positive‐ (PPA) and negative‐percent agreement (NPA) for HIV RDT results and the false‐HIV‐positivity rate for people with previous HIV‐positive results (“known‐positives”) were calculated using results from external quality assurance testing done for HIV surveillance purposes. Data on indicators of quality management systems, RDT kit performance under local climatic conditions and user/clerical errors were collected using HIV surveillance forms, data‐loggers and a Smartphone camera application (7 sites). Proportions of cases with errors were compared for tests done in the presence/absence of potential sources of errors.ResultsNPA was 99.9% for both pregnant women (N = 17224) and male partners (N = 2173). PPA was 90.0% (N = 1187) and 93.4% (N = 136) for women and men respectively. 3.5% (N = 1921) of known‐positive individuals on ART were HIV negative. Humidity and temperature exceeding manufacturers’ recommendations, particularly in storerooms (88.6% and 97.3% respectively), and premature readings of RDT output (56.0%) were common. False‐HIV‐negative cases, including interpretation errors, occurred despite staff training and good algorithm compliance, and were not reduced by existing external or internal quality assurance procedures. PPA was lower when testing room humidity exceeded 60% (88.0% vs. 93.3%; p = 0.007).ConclusionsFalse‐HIV‐negative results were still common in Zimbabwe in 2017 and could be reduced with HIV testing algorithms that use RDTs with higher sensitivity under real‐world conditions and greater practicality under busy clinic conditions, and by strengthening proficiency testing procedures in external quality assurance systems. New false‐HIV‐positive RDT results were infrequent but earlier errors in testing may have resulted in large numbers of uninfected individuals being on ART.

A review of 10 years of data from an external quality assurance program for antiphospholipid antibodies: no evidence for improved aCL and β2GPI assay standardization

Background: Anticardiolipin (aCL) and anti-β2-glycoprotein I (aβ2GPI) antibodies are important markers in the diagnosis of the antiphospholipid syndrome. Previous studies have shown significant variability in results obtained from different kits and manufacturers for these antibodies. In response to this lack of homogeneity, there have been international initiatives aimed at improving the reproducibility and standardization of these assays. To assess if these standardization initiatives have led to improved consistency in routine diagnostic laboratory reporting of these antibodies, we retrospectively reviewed 10 years of data from an External Quality Assurance (EQA) program. Methods: Data submitted by laboratories participating in the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) antiphospholipid EQA program over a ten-year period (2009–2018) for IgG and IgM aCL and IgG aβ2GPI antibodies were reviewed. Changes in assay methodologies, consensus of results against the target set by RCPAQAP, and the number of laboratories reporting semi-quantitative results were assessed. Results: Methodologies used for the detection of aCL and aβ2GPI antibodies have changed considerably since 2009, with a steady trend towards non-ELISA based methodologies, such as chemiluminescence, fluorescence immunoassay and Luminex based techniques. Consensus in resulting (defined as ≥80% concordance in reporting “negative” or “positive” results for a sample) did not significantly change across the 10-year period for any test. There was a significant decrease in the proportion of laboratories reporting semi-qualitative results (i.e., low/medium/high positive) for IgG aCL (P=0.0036) and IgG aβ2GPI antibodies (P=0.007). No significant change was noted for IgM aCL antibodies (P>0.999). Conclusions: Despite concerted efforts by a number of international groups to improve the standardization of aCL and aβ2GPI antibodies assays, a review of data obtained over a 10-year period of EQA testing in diagnostic laboratories demonstrated that there is no evidence to support that these efforts have translated into improvements in the consistency of IgG/IgM aCL and IgG aβ2GPI antibody results.

Results from 15 years of quality surveillance for a National Indigenous Point-of-Care Testing Program for diabetes

IntroductionDiabetes is a major health problem for Australia's Aboriginal and Torres Strait Islander peoples. Point-of-care testing for haemoglobin A1c (HbA1c) has been the cornerstone of a long-standing program (QAAMS) to manage glycaemic control in Indigenous people with diabetes and recently, to diagnose diabetes. MethodsThe QAAMS quality management framework includes monthly testing of quality control (QC) and external quality assurance (EQA) samples. Key performance indicators of quality include imprecision (coefficient of variation [CV%]) and percentage acceptable results. This paper reports on the past 15years of quality testing in QAAMS and examines the performance of HbA1c POC testing at the 6.5% cut-off recommended for diagnosis. ResultsThe total number of HbA1c EQA results submitted from 2002 to 2016 was 29,093. The median imprecision for EQA testing by QAAMS device operators averaged 2.81% (SD 0.50; range 2.2 to 3.9%) from 2002 to 2016 and 2.44% (SD 0.22; range 2.2 to 2.9%) from 2009 to 2016. No significant difference was observed between the median imprecision achieved in QAAMS and by Australasian laboratories from 2002 to 2016 (p=0.05; two-tailed paired t-test) and from 2009 to 2016 (p=0.17; two-tailed paired t-test). For QC testing from 2009 to 2016, imprecision averaged 2.5% and 3.0% for the two levels of QC tested. Percentage acceptable results averaged 90% for QA testing from 2002 to 2016 and 96% for QC testing from 2009 to 2016. The DCA Vantage was able to measure a patient and an EQA sample with an HbA1c value close to 6.5% both accurately and precisely. ConclusionHbA1c POC testing in QAAMS has remained analytically sound, matched the quality achieved by Australasian laboratories and met profession-derived analytical goals for 15years.

Quality assuring HIV point of care testing using whole blood samples

The Royal College of Pathologists Australasia Quality Assurance Programs (RCPAQAP), have offered dedicated external quality assurance (EQA) for HIV point of care testing (PoCT) since 2011. Prior to this, EQA for these tests was available within the comprehensive human immunodeficiency virus (HIV) module. EQA testing for HIV has typically involved the supply of serum or plasma, while in the clinic or community based settings HIV PoCT is generally performed using whole blood obtained by capillary finger-stick collection. RCPAQAP has offered EQA for HIV PoCT using stabilised whole blood since 2014. A total of eight surveys have been undertaken over a period of 2 years from 2014 to 2015. Of the 962 responses received, the overall consensus rate was found to be 98% (941/962). A total of 21 errors were detected. The majority of errors were attributable to false reactive HIV p24 antigen results (9/21, 43%), followed by false reactive HIV antibody results (8/21, 38%). There were 4/21 (19%) false negative HIV antibody results and no false negative HIV p24 antigen results reported. Overall performance was observed to vary minimally between surveys, from a low of 94% up to 99% concordant. Encouraging levels of testing proficiency for HIV PoCT are indicated by these data, but they also confirm the need for HIV PoCT sites to participate in external quality assurance programs to ensure the ongoing provision of high quality patient care.

Home-based counseling and testing for HIV and syphilis – an evaluation of acceptability and quality control, in remote Amazonas State, Brazil

ObjectiveHome-based, voluntary counselling and testing (HBCT) can help scale up early diagnosis. We aimed to evaluate the acceptance of HBCT for HIV and syphilis, estimate the prevalence among home-tested individuals...

Accuracy of Pima Point-of-Care CD4 Analyzer in Routine Use in Public Health Clinics in Uganda

1Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, Minnesota, USA 2Division of Infectious Diseases and International Medicine, Department of Medicine, University of Minnesota, Minneapolis, Minnesota, USA 3Infectious Disease Institute, Kampala, Uganda 4Makerere University College of Health Sciences, School of Medicine, Department of Medicine, Kampala, Uganda

Developing an Internal Quality Assurance Program for Immunohistochemistry Interpretation of Her–2/neu

The purpose of this initiative was to develop an in-house program that allows a comparison of pathologist interpretations of human epidermal growth factor receptor 2 gene (Her-2/neu) performed by immunohistochemistry (IHC). This comparison would drive uniformity in reporting between pathologists in the greater medical community and improve the precision of Her-2/neu interpretations and its utility as a predictive marker. The technical variance behind the process of Her-2/neu interpretations may lead to interpretative variability between pathologists. The technical variables were minimized by passing a single slide with a tissue microarray stained for Her-2/neu by IHC between pathologists at different laboratory sites for interpretation. The pathologist identities remained anonymous to the group. The results were reported by the pathologists to a single assessor. The results were compiled and distributed with each pathologist knowing only his/her own identification number as designated by the single assessor; 100% pathologist participation was achieved. The findings indicate a relatively consistent pattern of reporting between pathologists for Her-2/neu. By developing an internal quality assurance program to function in conjunction with external quality assurance testing, the technical staff and pathologists can collaboratively ensure optimal performance, interpretation, and reporting of results. (The J Histotechnol 33(2):85–92, 2010)Submitted December 22, 2009; accepted with revisions May 12, 2010.

Developing an Internal Quality Assurance Program for Immunohistochemistry Interpretation of Her–2/neu

The purpose of this initiative was to develop an in-house program that allows a comparison of pathologist interpretations of human epidermal growth factor receptor 2 gene (Her-2/neu) performed by immunohistochemistry (IHC). This comparison would drive uniformity in reporting between pathologists in the greater medical community and improve the precision of Her-2/neu interpretations and its utility as a predictive marker. The technical variance behind the process of Her-2/neu interpretations may lead to interpretative variability between pathologists. The technical variables were minimized by passing a single slide with a tissue microarray stained for Her-2/neu by IHC between pathologists at different laboratory sites for interpretation. The pathologist identities remained anonymous to the group. The results were reported by the pathologists to a single assessor. The results were compiled and distributed with each pathologist knowing only his/her own identification number as designated by the single assessor; 100% pathologist participation was achieved. The findings indicate a relatively consistent pattern of reporting between pathologists for Her-2/neu. By developing an internal quality assurance program to function in conjunction with external quality assurance testing, the technical staff and pathologists can collaboratively ensure optimal performance, interpretation, and reporting of results. (The J Histotechnol 33(2):85–92, 2010)Submitted December 22, 2009; accepted with revisions May 12, 2010.