RESUMEN
BACKGROUND: There are significant differences in plasma parathyroid hormone (PTH) results obtained by current immunoassay methods. However, many clinical guidelines relevant to patients with chronic kidney disease (CKD) that recommend PTH target values do not take account of these differences. This raises major questions about the validity of the evidence underpinning current use of PTH measurements in the management of CKD as well as of published relevant audit data. METHODS: PTH was measured in plasma from patients with CKD in six commercially available immunoassays. The initial pilot study included 19 patients while 98 patients were included in a second extended study. Data from the second study were analysed by regression analysis to obtain assay-specific targets for each immunoassay. RESULTS: Although similar PTH reference intervals are provided by most manufacturers, both studies confirmed substantial between-method differences in observed PTH for all patients, with results varying by as much as 4.2-fold between the lowest and highest reading methods. These differences were sufficient to have treatment implications for 79% of the patients in the pilot study. Applying the assay-specific targets derived here to results from the extended study decreased treatment misclassifications from 53% to 12%. CONCLUSIONS: Existing between-method differences in PTH measurements clearly have treatment implications. International initiatives to address these differences are in progress and will require support and input from all stakeholders. Adoption of assay-specific target values such as those reported here provides a convenient and practical interim solution that should lead to significant improvement in patient management, while also enabling meaningful audit.
Asunto(s)
Inmunoensayo/normas , Riñón/metabolismo , Hormona Paratiroidea/sangre , Insuficiencia Renal Crónica/diagnóstico , Humanos , Inmunoensayo/métodos , Riñón/fisiopatología , Guías de Práctica Clínica como Asunto , Estándares de Referencia , Valores de Referencia , Análisis de Regresión , Insuficiencia Renal Crónica/sangre , Insuficiencia Renal Crónica/fisiopatología , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
This study was performed to establish whether the "cam" impinging femur has a single deformity of the head-neck junction or multiple abnormalities. Average dimensions (anteversion angle, α angle of Notzli, ß angle of Beaulé, normalized anterior head offset) were compared between normal and impinging femora. The results demonstrated that impinging femora had wider necks, larger heads, and decreased head-neck ratios. There was no difference in neck-shaft angle or anteversion angle. Forty-six percent of impinging femora had significant posterior head displacement (>2mm), which averaged 1.93 mm for the cam impinging group, and 0.78 mm for the normal group. In conclusion, surgical treatment limited to localized recontouring of the head-neck profile may fail to address significant components of the underlying abnormality.
Asunto(s)
Cabeza Femoral/anomalías , Cuello Femoral/anomalías , Fémur/anomalías , Artropatías/etiología , Adulto , Anciano , Anciano de 80 o más Años , Cadáver , Femenino , Fémur/diagnóstico por imagen , Cabeza Femoral/diagnóstico por imagen , Cuello Femoral/diagnóstico por imagen , Humanos , Articulación de la Rodilla/anomalías , Masculino , Persona de Mediana Edad , Rango del Movimiento Articular , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Commutability of immunoassay test results is an important objective for laboratory medicine. METHODS: PSA is a clinically important analyte for which, as a consequence of a number of national and international initiatives over the last decade, considerable progress has been made towards improving method comparability. However, results from different assays are still not interchangeable, a situation that is only likely to improve once broad recommendations can be made about the most clinically relevant antibody combinations. CONCLUSIONS: Universal implementation of such recommendations would almost certainly improve between-method agreement substantially, provided careful attention were paid to assay design and use of appropriately pure secondary standards ensured.