Verification of examination procedures for 72 biochemical parameters on the atellica® clinical chemistry and immunoassay analyzers.

The verification of examination procedures is a responsibility for clinical laboratories in order to guarantee that their performance characteristics comply with the specifications obtained during the validation process and are congruent with the intended scope of the assay. The aim was to perform an evaluation of precision, bias, linearity, linear drift, sample carry-over, and comparability of 73 assays from Siemens Healthineers, by following the CLSI EP10-A3 guidelines. The verification was performed by measuring 72 biochemical parameters in quality control (QC) materials from Bio-Rad (except for IL6) with 73 assays installed on eight measuring systems (five Atellica® CH 930 and three IM 1600 analyzers from Siemens Healthcare Diagnostics). The following information was collected: validation data from manufacturer, biological variation data from the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) database, and specifications for fßhCG and PAPP-A assays to meet the Fetal Medicine Foundation standards. A total of 17550 results were obtained during EP10 verification process. Out of the 73 methods, only Cl-S, Mg-S, and Na-S failed the criteria for adequate precision, trueness, and comparability. The assays did not show significant loss of linearity, linear drift, or sample carry-over. This study allowed the initial training and familiarization with the instruments and the identification of operational issues. It also represented an opportunity to evaluate the QCs and to obtain analytical performance information for application of sigma six metrics for quality assurance. Professionals are advised to adequately standardize and protocolize their verification processes to ensure laboratory competence and patient safety.

Management of postanalytical processes in the clinical laboratory according to ISO 15189:2012 Standard requirements: considerations on the review, reporting and release of results.

The objective of this paper is to share some considerations about the management of postanalytical processes in relation to the review, reporting and release of test results in accordance with UNE-EN ISO 15189:2013 Standard requirements. The scope of this paper includes postanalytical activities and the personnel involved (laboratory management and staff). We describe the criteria and information required to review and validate analytical results and ensure that clear reports are sent to requesters. These criteria also guarantee that results are transcribed in a reliable way and that all necessary information is provided for the correct interpretation of results. Likewise, the requirements for the correct release of laboratory results are described, with special emphasis on the release of alarming or critical results. In some European countries, clinical laboratories are required to hold partial or full ISO 15189 accreditation, which is a global trend. Therefore, understanding ISO 15189 requirements is imperative for a progressive and more effective implementation of the Standard.

Defects in memory B-cell and plasma cell subsets expressing different immunoglobulin-subclasses in patients with CVID and immunoglobulin subclass deficiencies.

BACKGROUND: Predominantly antibody deficiencies (PADs) are the most prevalent primary immunodeficiencies, but their B-cell defects and underlying genetic alterations remain largely unknown. OBJECTIVE: We investigated patients with PADs for the distribution of 41 blood B-cell and plasma cell (PC) subsets, including subsets defined by expression of distinct immunoglobulin heavy chain subclasses. METHODS: Blood samples from 139 patients with PADs, 61 patients with common variable immunodeficiency (CVID), 68 patients with selective IgA deficiency (IgAdef), 10 patients with IgG subclass deficiency with IgA deficiency, and 223 age-matched control subjects were studied by using flow cytometry with EuroFlow immunoglobulin isotype staining. Patients were classified according to their B-cell and PC immune profile, and the obtained patient clusters were correlated with clinical manifestations of PADs. RESULTS: Decreased counts of blood PCs, memory B cells (MBCs), or both expressing distinct IgA and IgG subclasses were identified in all patients with PADs. In patients with IgAdef, B-cell defects were mainly restricted to surface membrane (sm)IgA+ PCs and MBCs, with 2 clear subgroups showing strongly decreased numbers of smIgA+ PCs with mild versus severe smIgA+ MBC defects and higher frequencies of nonrespiratory tract infections, autoimmunity, and affected family members. Patients with IgG subclass deficiency with IgA deficiency and those with CVID showed defects in both smIgA+ and smIgG+ MBCs and PCs. Reduced numbers of switched PCs were systematically found in patients with CVID (absent in 98%), with 6 different defective MBC (and clinical) profiles: (1) profound decrease in MBC numbers; (2) defective CD27+ MBCs with almost normal IgG3+ MBCs; (3) absence of switched MBCs; and (4) presence of both unswitched and switched MBCs without and; (5) with IgG2+ MBCs; and (6) with IgA1+ MBCs. CONCLUSION: Distinct PAD defective B-cell patterns were identified that are associated with unique clinical profiles.

Age-associated distribution of normal B-cell and plasma cell subsets in peripheral blood.

BACKGROUND: Humoral immunocompetence develops stepwise throughout life and contributes to individual susceptibility to infection, immunodeficiency, autoimmunity, and neoplasia. Immunoglobulin heavy chain (IgH) isotype serum levels can partly explain such age-related differences, but their relationship with the IgH isotype distribution within memory B-cell (MBC) and plasma cell (PCs) compartments remains to be investigated. OBJECTIVE: We studied the age-related distribution of MBCs and PCs expressing different IgH isotypes in addition to the immature/transitional and naive B-cell compartments. METHODS: B-cell and PC subsets and plasma IgH isotype levels were studied in cord blood (n = 19) and peripheral blood (n = 215) from healthy donors aged 0 to 90 years by using flow cytometry and nephelometry, respectively. RESULTS: IgH-switched MBCs expressing IgG1, IgG2, IgG3, IgA1, and IgA2 were already detected in cord blood and newborns at very low counts, whereas CD27+IgM++IgD+ MBCs only became detectable at 1 to 5 months and remained stable until 2 to 4 years, and IgD MBCs peaked at 2 to 4 years, with both populations decreasing thereafter. MBCs expressing IgH isotypes of the second immunoglobulin heavy chain constant region (IGHC) gene block (IgG1, IgG3, and IgA1) peaked later during childhood (2-4 years), whereas MBCs expressing third IGHC gene block immunoglobulin isotypes (IgG2, IgG4, and IgA2) reached maximum values during adulthood. PCs were already detected in newborns, increasing in number until 6 to 11 months for IgM, IgG1, IgG2, IgG3, IgA1, and IgA2; until 2 to 4 years for IgD; and until 5 to 9 years for IgG4 and decreasing thereafter. For most IgH isotypes (except IgD and IgG4), maximum plasma levels were reached after PC and MBC counts peaked. CONCLUSIONS: PC counts reach maximum values early in life, followed by MBC counts and plasma IgH isotypes. Importantly, IgH isotypes from different IGHC gene blocks show different patterns, probably reflecting consecutive cycles of IgH isotype switch recombination through life.

Gestión de los procesos preanalíticos en los laboratorios clínicos según los requisitos de la Norma UNE-EN ISO 15189: 2013. Recomendación (2015) / Management of pre-analytical processes in clinical laboratories as required by Rule UNE-EN ISO 15189: 2013. Recommendation (2015)

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