Elaboration of reference material for cadmium and arsenic in hydrobiological products, for the purpose of being used in a laboratory intercomparation program / Elaboración de un material de referencia para cadmio y arsénico en productos hidrobiológicos, para propósito de ser utilizado en un programa de intercomparación de laboratorios

Reference materials (RM) are tools used in the comparability and traceability of measurements. They are widely used by laboratories for method validation and quality control of assay. Chile must evaluate theperformance of laboratories that analyzing metals in fishery products, despite RM have high prices and are scarce. For that reason, a RM in a hydrobiological product was developed. Reference values for arsenic and cadmium elements for a fishmeal were assigned. The measurement methods for characterization of the material were Inductively Coupled Plasma Mass Spectrometry, Atomic Absorption Spectrometry and Neutron Activation Analysis. Reference values with their expanded uncertainty (U) were established for arsenic 2.64 ± 0.42 mg/kg (U; k = 2) and for cadmium 0.86 ± 0.16 mg/kg (U; k = 2). Homogeneity and stability of the RM allowed its use in a proficiency test for eleven food control laboratories. Results for median were 2.114 mg/kg for arsenic, and 0.863 mg/kg for cadmium. The performance values of the participants were evaluated with a z score obtaining 60% satisfaction for arsenic and 73% for cadmium.The material demonstrated to be suitable for use in interlaboratory proficiency assay. (AU)

Materiales de referencia (MR) son herramientas utilizadas en la comparabilidad y trazabilidad entre mediciones. Laboratorios los utilizan ampliamente en validación de métodos y control de calidad. Chile debe evaluar el desempeño de los laboratorios que analizan metales en productos pesqueros, a pesar de los altos precios y escasez del MR. Por esa razón, se desarrolló un MR en producto hidrobiológico. Se asignaron valores de referencia para arsénico y cadmio en harina de pescado. Los métodos de medición para la caracterización del material fueron Espectrometría de Masas de Plasma Acoplado Inductivamente, Espectrometría de Absorción Atómica y Análisis de Activación de Neutrones. Se establecieron valores de referencia con su incertidumbre (U) para arsénico 2.64 ± 0.42 mg/kg (U; k = 2) y para cadmio 0.86 ± 0.16 mg/kg (U; k = 2). La homogeneidad y estabilidad del MR permitieron su uso en una prueba de aptitud para once laboratorios de control de alimentos. Las medianas fueron 2,114 mg/kg para arsénico y 0,863 mg/kg para cadmio. Se evaluaron los rendimientos de los participantes con un estadístico de puntaje z satisfactorio del 60% para el arsénico y 73% para el cadmio. El material demostró ser adecuado para uso en ensayo de aptitud de intercomparación. (AU)

Survey Analysis of ABO Antibody Titration at Four University Hospitals in Korea / 대한수혈학회지

BACKGROUND: The ABO antibody titration is important, especially in case of ABO-incompatible hemolytic disease of newborn, ABO-incompatible bone marrow or solid organ transplantation. However, no standard method for ABO antibody titration has yet been established. We surveyed four university hospitals about the methods of ABO antibody titration and performed inter-laboratory proficiency tests. METHODS: Detailed methods of ABO antibody titration were surveyed at four university hospitals. ABO antibody titer was measured by their customary methods using serum samples from six healthy volunteers with blood groups A (n=2), B (n=2) and O (n=2). RESULTS: Procedures of ABO antibody titration, reportable ranges, sample diluent, source of reagent RBCs and interpretation of end-point were different among four university hospitals. Inter-institutional maximum differences of IgM and IgG ABO antibody titer were 16-fold and 32-fold, respectively. CONCLUSION: Standardization of ABO antibody titration method is needed to reduce inter-laboratory variability, and a periodical external quality control survey is necessary to improve the accuracy of the titration.