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Alsina M.J.,Laboratori Clinic Barcelones Nord i Valles Oriental | Biosca C.,Hospital Universitari Germans Trias i Pujol | Serrat N.,Hospital Universitari Joan | Montesinos M.,Hospital Universitari Doctor Josep Trueta | And 7 more authors.
Revista del Laboratorio Clinico | Year: 2015

Introduction: Hemolysis, turbidity and the presence of high concentrations of bilirubin are the most frequent sources of interference in the clinical laboratory. Many analyzers incorporate detection systems for these interferents called "serum indexes" of hemolysis, icterus and lipidemia. The accuracy of such indexes is usually not verified by the difficulty in obtaining appropriate reference materials. In this work we show the results of an interlaboratory study of hemolysis, icterus and lipidemia indexes using reference materials containing known concentrations of these interfering substances. Material and methods: Ten clinical laboratories from different centres have participated in the study using 7 different analyzers. The reference materials for the serum indexes contained known concentrations of bilirubin, hemoglobin (hemolysate) and triglycerides (Intralipid). Results: All instruments provided acceptable results for the icterus and hemolysis index. Among the analyzers providing quantitative values, low results were found in one of the analyzers for materials containing Intralipid. The analyzers expressing the result as an interval provided correct results for materials with low turbidity but a low result for the material with the highest turbidity. Conclusions: The reference materials used have proved to be useful to verify the serum indexes for hemolysis, icterus and lipidemia in analyzers. The results obtained in different instruments generally agree among them and with the assigned values. The most important differences between analyzers were found in the lipidemia index. © 2014 AEBM, AEFA y SEQC. Source


Perich C.,SEQC Analytical Quality Commission | Perich C.,Laboratori Clinic Bon Pastor | Ricos C.,SEQC Analytical Quality Commission | Alvarez V.,SEQC Analytical Quality Commission | And 18 more authors.
Clinica Chimica Acta | Year: 2014

Introduction: Current external quality assurance schemes have been classified into six categories, according to their ability to verify the degree of standardization of the participating measurement procedures. SKML (Netherlands) is a Category 1 EQA scheme (commutable EQA materials with values assigned by reference methods), whereas SEQC (Spain) is a Category 5 scheme (replicate analyses of non-commutable materials with no values assigned by reference methods). Aim: The results obtained by a group of Spanish laboratories participating in a pilot study organized by SKML are examined, with the aim of pointing out the improvements over our current scheme that a Category 1 program could provide. Method: Imprecision and bias are calculated for each analyte and laboratory, and compared with quality specifications derived from biological variation. Results: Of the 26 analytes studied, 9 had results comparable with those from reference methods, and 10 analytes did not have comparable results. The remaining 7 analytes measured did not have available reference method values, and in these cases, comparison with the peer group showed comparable results. The reasons for disagreement in the second group can be summarized as: use of non-standard methods (IFCC without exogenous pyridoxal phosphate for AST and ALT, Jaffé kinetic at low-normal creatinine concentrations and with eGFR); non-commutability of the reference material used to assign values to the routine calibrator (calcium, magnesium and sodium); use of reference materials without established commutability instead of reference methods for AST and GGT, and lack of a systematic effort by manufacturers to harmonize results. Conclusions: Results obtained in this work demonstrate the important role of external quality assurance programs using commutable materials with values assigned by reference methods to correctly monitor the standardization of laboratory tests with consequent minimization of risk to patients. © 2013 Elsevier B.V. Source


Ruiz R.,Laboratori Clinic LHospitalet | Llopis M.A.,Laboratori Clinic Barcelones Nord i Valles Oriental | Biosca C.,Servei de Bioquimica Clinica Hospital Germans Trias i Pujol | Trujillo G.,Laboratori Clinic Bages | And 14 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2010

Background: Quality specifications for indicators of the key analytic processes have been defined by international consensus. However, only preliminary specifications for laboratory-related strategic and support processes have been developed. The present study attempts to increase the robustness of the preliminary proposed specifications. Methods: Recovering records and incidences occurred over a 4-year follow-up period, for 12 indicators, used in all laboratories from this group regarding strategic and support processes. Results and conclusions: The results obtained indicate that it is better to establish an interval rather than a fixed value for the majority of indicators. Longer studies are needed to properly assess some quality specifications, and data recording system must be standardized in others. Additional, multicenter studies are needed to establish more robust specifications and determine the state of the art of laboratories in other settings. © 2010 by Walter de Gruyter, Berlin, New York. Source


Fernandez P.,Institute Catala Of La Salut Ics | Llopis M.A.,Laboratori Clinic Barcelones Nord i Valles Oriental | Perich C.,Laboratori Clinic Bon Pastor | Alsina M.J.,Laboratori Clinic Barcelones Nord i Valles Oriental | And 13 more authors.
Clinical Chemistry and Laboratory Medicine | Year: 2014

Background: Hemolysis is the main cause of non-quality samples in clinical laboratories, producing the highest percentage of rejections in the external assurance programs of preanalytical quality. The objective was to: 1) study the agreement between the detection methods and quantification of hemolysis; 2) establish comparable hemolysis interference limits for a series of tests and analytical methods; and 3) study the preanalytical variables which most influence hemolysis production.Methods: Different hemoglobin concentration standards were prepared using the reference method. Agreement was studied between automated methods [hemolytic indexes (HI)] and reference method, as well as the interference according to hemolysis degree in various biochemical tests was measured. Preanalytical variables which could influence hemolysis production were studied: type of extraction, type of tubes, transport time, temperature and centrifugation conditions.Results: Good agreement was obtained between hemoglobin concentrations measured using the reference method and HI, for the most of studied analyzers, particularly those giving quantitative HI. The hemolysis interference cut-off points obtained for the majority of tests studied (except LDH, K) are dependent on the method/analyzer utilized. Furthermore, discrepancies have been observed between interference limits recommended by the manufacturer. The preanalytical variables which produce a lower percentage of hemolysis rejections were: centrifugation at the extraction site, the use of lower volume tubes and a transport time under 15 min at room temperature.Conclusions: The setting of interference limits (cut-off) for each used test/method, and the study of preanalytical variability will assist to the results harmonization for this quality indicator. Source

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