RESUMEN
Over 30 years since it was first described as a discrete clinical entity, the antiphospholipid antibody syndrome (APS) remains a challenge for both laboratory workers and clinicians in a wide range of specialties. In addition to the presence of appropriate clinical features, the diagnosis of APS also fundamentally requires the finding of positive antiphospholipid antibody (aPL) test result(s), which comprise clot-based assays for the identification of lupus anticoagulant (LA) and immunologic ("solid-phase") assays such as anticardiolipin antibodies (aCL) and anti-ß2-glycoprotein I antibodies (aß2GPI). This article is the first of two that review the process for, and provides recommendations to improve, internal quality control (IQC) and external quality assurance (EQA; or proficiency testing) for aPL assays. These processes are critical for ensuring the quality of laboratory test results and thence the appropriate clinical diagnosis and management of APS. This article covers aCL and aß2GPI testing. In brief, IQC is a process that helps control the quality of laboratory test results on a test-by-test basis; IQC should include samples that provide values around the assay critical cut-off values, and there is added value in the inclusion of non-kit assay controls. EQA is a process that helps laboratories assess their performance against those of their peers. For aCL and aß2GPI testing, we provide some updated findings from the Royal College of Pathologists of Australasia Immunology Quality Assurance Program, and covering testing for the past 3 years (2009 to 2011 inclusive). Findings show similar trends to past years, indicating limited improvement in cross-laboratory test results and interpretations. In summary: (1) EQA participants reported greatly varying numerical test data for both aCL and aß2GPI, with interlaboratory coefficients of variation > 50% with most test challenges; (2) there was considerable overlap in the interpretation (negative, positive, low positive, moderate positive, strong positive) that different participants ascribed to identical numerical test results; and (3) there was limited consensus among participants as to whether test results for individual EQA specimens were either positive or negative for aCL and/or aß2GPI.
Asunto(s)
Anticuerpos Anticardiolipina/análisis , Anticuerpos Antifosfolípidos/análisis , beta 2 Glicoproteína I/inmunología , Anticuerpos Anticardiolipina/inmunología , Anticuerpos Antifosfolípidos/sangre , Anticuerpos Antifosfolípidos/inmunología , Femenino , Humanos , Embarazo , Complicaciones del Embarazo/sangre , Complicaciones del Embarazo/inmunología , Garantía de la Calidad de Atención de Salud/métodos , Control de CalidadRESUMEN
BACKGROUND: Although protein electrophoresis of serum (SPEP) and urine (UPEP) specimens is a well-established laboratory technique, the reporting of results using this important method varies considerably between laboratories. The Australasian Association of Clinical Biochemists recognized a need to adopt a standardized approach to reporting SPEP and UPEP by clinical laboratories. METHODS: A Working Party considered available data including published literature and clinical studies, together with expert opinion in order to establish optimal reporting practices. A position paper was produced, which was subsequently revised through a consensus process involving scientists and pathologists with expertise in the field throughout Australia and New Zealand. RESULTS: Recommendations for standardized reporting of protein electrophoresis have been produced. These cover analytical requirements: detection systems; serum protein and albumin quantification; fractionation into alpha-1, alpha-2, beta and gamma fractions; paraprotein quantification; urine Bence Jones protein quantification; paraprotein characterization; and laboratory performance, expertise and staffing. The recommendations also include general interpretive commenting and commenting for specimens with paraproteins and small bands together with illustrative examples of reports. CONCLUSIONS: Recommendations are provided for standardized reporting of protein electrophoresis in Australia and New Zealand. It is expected that such standardized reporting formats will reduce both variation between laboratories and the risk of misinterpretation of results.
Asunto(s)
Proteínas Sanguíneas/análisis , Electroforesis/normas , Proyectos de Investigación/normas , Australia , Recolección de Datos/normas , Humanos , Inmunoglobulinas/sangre , Laboratorios/normas , Personal de Laboratorio Clínico , Nueva Zelanda , Paraproteínas/análisis , Orina/químicaRESUMEN
Most laboratories screen for antineutrophil cytoplasmic antibodies (ANCA) with indirect immunofluorescence (IIF) and confirm cytoplasmic (C-ANCA) and perinuclear (P-ANCA) staining with ELISAs for proteinase 3 (PR3) and myeloperoxidase (MPO) specificities. This study determined the concordance of ANCA test results from 48 diagnostic laboratories participating in a national Quality Assurance programme, that used different assays and methods and varied in expertise. Laboratories were circulated with a questionnaire about their techniques, and provided with 24 sera for testing over a 30 month period. Results for individual sera were compared with the 'observed consensus' found in more than 50% of laboratories. The 23 laboratories (48%) that responded to the questionnaire used 5 different IIF substrates and 11 ELISAs, and differed in other aspects of testing. Concordance for ANCA test results was greater for IIF-positive (n=22, median 96%, range 68%-100%) than an IIF-negative serum (median 64%); for C-ANCA (n=8, median 89%, range 66-100%) rather than P-ANCA (n=10, median 76%, range 52-88%); for MPO-ANCA (n=5, median 100%) rather than PR3-ANCA (n=7, median 89%, range 82-100%); and for strongly-positive (n=2, median 97%, range 96-97%) rather than low positive PR3-ANCA (n=4, median 80%, range 74-86%). Concordance for test results might be improved with further standardisation of testing methodologies.