State of affairs and future challenges in laboratory medicine in Spain: an analysis of the Spanish Society of Laboratory Medicine (SEQCML).

Objectives: Laboratory Medicine is a crucial discipline that contributes to the diagnosis, management and monitoring of patients. This branch of medicine faces two major challenges: New technologies and increased demand. There is limited information available of the state of affairs in Laboratory Medicine in Spain. This study provides a picture of clinical laboratories and clinical laboratory professionals. Methods: The Spanish Society of Laboratory Medicine distributed a questionnaire among the 250 most representative centers (the ones with the largest volume of determinations and training programs), of which 174 (69.6%) returned the questionnaire providing data for 2019. Results: Laboratories were classified according to the number of determinations. In total, 37% identified themselves as small (<1 million determinations per year); 40% considered themselves medium-sized (1-5 million determinations per year) and 23% considered they were large laboratories (>5 million determinations). The level of specialization of laboratory physicians and laboratory performance were higher in large laboratories. Most requests (87%) and determinations (93%) corresponded to biochemistry and hematology. As many as 63% of physicians had an indefinite contract, and 23% were older than 60 years. Conclusions: Laboratory medicine is a consolidated discipline that is gaining relevance in Spain. It adds value to the diagnosis, prognosis and follow-up of diseases, and to treatment response monitoring. The results of this study will help us address challenges such as the need for specialized training for laboratory professionals; the emergence of technological innovations; exploitation of Big Data; optimization of quality management systems and patient safety.

The Increase in FGF23 Induced by Calcium Is Partially Dependent on Vitamin D Signaling.

BACKGROUND: Increased FGF23 levels are an early pathological feature in chronic kidney disease (CKD), causing increased cardiovascular risk. The regulation of FGF23 expression is complex and not completely understood. Thus, Ca2+ has been shown to induce an increase in FGF23 expression, but whether that increase is mediated by simultaneous changes in parathyroid hormone (PTH) and/or vitamin D is not fully known. METHODS: Osteoblast-like cells (OLCs) from vitamin D receptor (VDR)+/+ and VDR-/- mice were incubated with Ca2+ for 18 h. Experimental hypercalcemia was induced by calcium gluconate injection in thyro-parathyroidectomized (T-PTX) VDR +/+ and VDR-/- mice with constant PTH infusion. RESULTS: Inorganic Ca2+ induced an increase in FGF23 gene and protein expression in osteoblast-like cells (OLCs), but the increase was blunted in cells lacking VDR. In T-PTX VDR +/+ and VDR-/- mice with constant PTH levels, hypercalcemia induced an increase in FGF23 levels, but to a lower extent in animals lacking VDR. Similar results were observed in FGF23 expression in bone. Renal and bone 1α-hydroxylase expression was also modulated. CONCLUSIONS: Our study demonstrates that Ca2+ can increase FGF23 levels independently of vitamin D and PTH, but part of the physiological increase in FGF23 induced by Ca2+ is mediated by vitamin D signaling.

Elimination of Vitamin D Signaling Causes Increased Mortality in a Model of Overactivation of the Insulin Receptor: Role of Lipid Metabolism.

Vitamin D (VD) deficiency has been associated with cancer and diabetes. Insulin signaling through the insulin receptor (IR) stimulates cellular responses by activating the PI3K/AKT pathway. PTEN is a tumor suppressor and a negative regulator of the pathway. Its absence enhances insulin signaling leading to hypoglycemia, a dangerous complication found after insulin overdose. We analyzed the effect of VD signaling in a model of overactivation of the IR. We generated inducible double KO (DKO) mice for the VD receptor (VDR) and PTEN. DKO mice showed severe hypoglycemia, lower total cholesterol and increased mortality. No macroscopic tumors were detected. Analysis of the glucose metabolism did not show clear differences that would explain the increased mortality. Glucose supplementation, either systemically or directly into the brain, did not enhance DKO survival. Lipidic liver metabolism was altered as there was a delay in the activation of genes related to ß-oxidation and a decrease in lipogenesis in DKO mice. High-fat diet administration in DKO significantly improved its life span. Lack of vitamin D signaling increases mortality in a model of overactivation of the IR by impairing lipid metabolism. Clinically, these results reveal the importance of adequate Vitamin D levels in T1D patients.

Effects of the COVID-19 pandemic on the activity of clinical laboratories in Spain, evolution in the 2019-2021 period.

Objectives: To assess the impact of the COVID-19 pandemic on the activity of clinical laboratories in Spain. Methods: A descriptive, observational, retrospective, multicenter study. Results: Between March and December 2020, there was a statistically significant decrease in the number of test requests (-17.7%, p=<0.001) and total tests performed (-18.3%, p<0.001) with respect to the same period in 2019. A decrease was observed in the number of requests from primary care (-37.4%) (p<0.001) and in the number of foecal occult blood (-45.8%); qualitative urine (-30.1%); PSA (-28.5%); TSH (-27.8%); total cholesterol (-27.2%) and HbA1c (-24.7%) tests performed, p<0.001. A significant increase was found in the number of requests from ICUs (76.6%, p<0.001) and number of IL-6 (+22,350.9), D-dimer (+617.2%), troponin (+46.8%) and arterial blood gas (+3.9%) tests carried out, p<0.001. During the first months of 2021, there were significant changes in the number of requests for qualitative urine (-8.7%, p<0.001), PSA (-6.3%, p=0.009), IL-6 (+66,269.2, p<0.001), D-dimer (+603.6%, p<0.001), troponin (+28.7%, p<0.001), arterial blood gas (+26,2%, p=0.014) and ferritin (+16.0%, p=0.002) tests performed. Conclusions: There were changes in the origin and number of test requested to clinical laboratories in Spain. The number of requests for the evaluation and monitoring of COVID-19 patients increased, whereas requests for the control of non-COVID patients and for population screening decreased. Long-term analysis reveals that the volume of tests performed for the control of chronic diseases returned to normal over time, whereas the increase observed in the volume of tests performed for the management of COVID-19 patients is maintained.

E-gene RT-PCR Crossing Point Value and Other Biochemical Parameters as Useful Markers of Death Risk in COVID-19 Patients.

The identification of laboratory markers which predict the outcome of COVID-19 patients is a great concern. Real-time reverse transcriptase-polymerase chain reaction (RT-PCR) has been used to confirm the clinical diagnosis. The aim of this study is to evaluate laboratory parameters of COVID-19 patients as well as to evaluate the RT-PCR crossing point (Cp) value and correlate blood test abnormalities and the Cp value with patients survival. Two hundred thirty patients with positive RT-PCR of SARS-CoV-2 were included in the study. Molecular diagnosis of SARS-CoV-2 was performed by RT-PCR (LightMix, TibMolbiol, Germany). Clinical information, biochemical parameters and Cp values were collected in an anonymized database and variables were analyzed with SPSS v25.0 (IBM Corporation, Armonk, NY, USA). No-survivors were significantly older (>65 years old) than survivors (p=0.007). A higher prevalence of cardiovascular comorbidities in patients who died than in those who survived was found (p=0.002). Statistically significant differences were obtained comparing RT-PCR Cp values for the E-gene of patients who died and those who survived, being lower (<=28) those of patients who died (p=0.004). No-survivors had significantly higher levels of CRP (>100) (p=0.007). E-gene Cp values <=28, which correlate with a high number of copies of SARS-CoV-2, as well as several demographical and biochemical parameters (Age above 65 years old, CRP levels >100 mg/L or cardiovascular comorbidities) could be useful markers of death risk in these patients.

Magnesium Levels Modify the Effect of Lipid Parameters on Carotid Intima Media Thickness.

Classical risk factors of atherosclerosis in the general population show paradoxical effects in chronic kidney disease (CKD) patients. Thus, low low-density lipoprotein (LDL) cholesterol levels have been associated with worse cardiovascular outcomes. Magnesium (Mg) is a divalent cation whose homeostasis is altered in CKD. Furthermore, Mg levels have been associated with cardiovascular health. The present study aims to understand the relationships of Mg and lipid parameters with atherosclerosis in CKD. In this analysis, 1754 participants from the Observatorio Nacional de Atherosclerosis en Nefrologia (NEFRONA) cohort were included. Carotid intima media thickness (cIMT) was determined in six arterial territories, and associated factors were investigated by linear regression. cIMT correlated positively with being male, Caucasian, a smoker, diabetic, hypertensive, dyslipidemic and with increased age, BMI, and triglyceride levels, and negatively with levels of HDL cholesterol. First-order interactions in linear regression analysis showed that Mg was an effect modifier on the influence of lipidic parameters. Thus, cIMT predicted values were higher when triglycerides or LDL levels were high and Mg levels were low. On the contrary, when Mg levels were high, this effect disappeared. In conclusion, Mg acts as an effect modifier between lipidic parameters and atherosclerotic cardiovascular disease. Therefore, Mg levels, together with lipidic parameters, should be taken into account when assessing atherosclerotic risk.

Reaching consensus on communication of critical laboratory results using a collective intelligence method.

BACKGROUND: There is no consensus in the literature about what analytes or values should be informed as critical results and how they should be communicated. The main aim of this project is to establish consensual standards of critical results for the laboratories participating in the study. Among the project's secondary objectives, establishing consensual procedures for communication can be highlighted. METHODS: Consensus was reached among all participating laboratories establishing the basis for the construction of the initial model put forward for consensus in conjunction with the clinicians. A real-time Delphi, methodology "health consensus" (HC), with motivating and participative questions was applied. The physician was expected to choose a numeric value within a scale designed for each analyte. RESULTS: The medians of critical results obtained represent the consensus on critical results for outpatient and inpatient care. Both in primary care and in hospital care a high degree of consensus was observed for critical values proposed in the analysis of creatinine, digoxin, phosphorus, glucose, international normalized ratio (INR), leukocytes, magnesium, neutrophils, chloride, sodium, calcium and lithium. For the rest of critical results the degree of consensus obtained was "medium high". The results obtained showed that in 72% of cases the consensual critical value coincided with the medians initially proposed by the laboratories. CONCLUSIONS: The real-time Delphi has allowed obtaining consensual standards for communication of critical results among the laboratories participating in the study, which can serve as a basis for other organizations.

Spanish Preanalytical Quality Monitoring Program (SEQC), an overview of 12 years' experience.

BACKGROUND: Preanalytical variables, such as sample collection, handling and transport, may affect patient results. Preanalytical phase quality monitoring should be established in order to minimize laboratory errors and improve patient safety. METHODS: A retrospective study (2001-2013) of the results obtained through the Spanish Society of Clinical Biochemistry and Molecular Pathology (SEQC) External quality assessment (preanalytical phase) was performed to summarize data regarding the main factors affecting preanalytical phase quality. Our aim was to compare data from 2006 to 2013 with a previously published manuscript assessing the 2001-2005 period. RESULTS: A significant decrease in rejection rates was observed both for blood and urine samples. For serum samples, the most frequent rejection causes in the first period were non-received samples (37.5%), hemolysis (29.3%) and clotted samples (14.4%). Conversely, in the second period, hemolysis was the main rejection cause (36.2%), followed by non-received samples (34.5%) and clotted samples (11.1%). For urine samples, the main rejection cause overall was a non-received sample (up to 86.1% of cases in the second period, and 81.6% in the first). For blood samples with anticoagulant, the number of rejections also decreased. While plasma-citrate-ESR still showed the highest percentages of rejections (0.980% vs. 1.473%, p<0.001), the lowest corresponded to whole-blood EDTA (0.296% vs. 0.381%, p<0.001). CONCLUSIONS: For the majority of sample types, a decrease in preanalytical errors was confirmed. Improvements in organization, implementation of standardized procedures in the preanalytical phase, and participation in a Spanish external quality assessment scheme may have notably contributed to error reduction in this phase.

Quality indicators for extra-analytical processes in clinical laboratory: ten years’ experience / Indicadores de calidad para los procesos extra-analíticos en el laboratorio clínico: 10 años de experiencia

Introduction. The selection and definition of quality indicators is essential for proper control of processes. This is not always easy, particularly with extra-analytical indicators, due to the complexity and degree of comparison of processes between laboratories, and the fact that data collection is not always automated. For this reason, the indicators and specifications need to be dynamic and re-designed in accordance with changes in the system. The aim of this paper is to describe the methodology used in the selection and definition of quality indicators, and their specifications for extra-analytical processes in public laboratories in Catalonia. Material and methods. During the study period (2004-2013), the members of the working group reported the mean annual value for each indicator, and the overall yearly mean of all participants was calculated. These results were compared and analyzed during periodic meetings, with regards to the pre-established specifications of the different laboratories. Results. Quality indicators and their specifications are presented. The evaluation of the validity of each quality indicator was made taking into account aspects including usefulness of the indicator in process monitoring, a clear definition, and a precise and reliable quantification. This methodology has made it possible to contrast the validity of the indicators or to reconsider the specification. Conclusions. The last 10 years’ experience of the Catalonian Health Institute Working Group on Quality Indicators in designing indicators and establishing quality specifications has proved very useful for improving the monitoring of processes in clinical laboratories included in the group (AU)

Introducción. La selección y definición de los indicadores de la calidad es imprescindible para controlar adecuadamente un proceso. Ello no siempre es fácil, sobre todo en el caso de los indicadores extraanalíticos, dada la complejidad y grado de comparabilidad de los procesos entre laboratorios y la necesaria recogida de datos que en muchas ocasiones no está automatizada. Asimismo, los indicadores y especificaciones deben ser dinámicos y rediseñarse en función de los cambios del sistema. El objetivo de este trabajo es describir la metodología utilizada en la selección y definición de indicadores de calidad y especificaciones para los procesos extraanalíticos en los laboratorios públicos de Cataluña. Material y métodos. Durante el período de estudio (2004-2013), los miembros del grupo han informado del valor medio anual para cada indicador, y se ha calculado la media anual de todos los participantes para cada uno de ellos. Estos resultados se han comparado y analizado a través de reuniones periódicas, con respecto a las especificaciones preestablecidas de los diferentes laboratorios. Resultados. Se presentan los indicadores de calidad y sus especificaciones. La evaluación de la validez de cada indicador de calidad se llevó a cabo teniendo en cuenta los aspectos incluyendo la utilidad del indicador en la supervisión de procesos, una definición clara y una cuantificación precisa y fiable. Esta metodología ha permitido contrastar la validez de los indicadores o reconsiderar la especificación. Conclusiones. Los últimos 10 años de experiencia del Grupo de Trabajo del Instituto Catalán de la Salud de Indicadores de Calidad en el diseño de indicadores y en establecer especificaciones de calidad ha demostrado ser muy útil para mejorar el seguimiento de los procesos en los laboratorios clínicos integrados en el grupo (AU)

Evaluación multicéntrica de materiales para el control de calidad de los índices séricos / Multicenter evaluation of materials for the quality control of the serum indexes

Introducción. La hemólisis, la turbidez y la presencia de concentraciones elevadas de bilirrubina son las fuentes de interferencia más frecuentes en el laboratorio clínico. Muchos analizadores incorporan sistemas de detección de estos interferentes denominados «índices séricos» de hemólisis, ictericia y lipidemia. El grado de veracidad de los índices no suele ser verificado por la dificultad en conseguir materiales de referencia adecuados. En este trabajo se presentan los resultados de un estudio interlaboratorios de los índices hemólisis, ictericia y lipidemia empleando materiales de referencia con concentraciones conocidas de los interferentes. Material y métodos. En el estudio han participado los laboratorios clínicos de 10 centros con 7 analizadores distintos. Los materiales de referencia de índices séricos contenían concentraciones conocidas de bilirrubina, hemoglobina (hemolisado) y triglicéridos (Intralipid). Resultados. Todos los instrumentos proporcionaron resultados aceptables para el índice de ictericia y de hemólisis. Entre los analizadores que dan valores cuantitativos se encontraron resultados bajos en uno de los analizadores para los materiales que contenían Intralipid. Los analizadores que expresan el resultado en forma de un intervalo proporcionaron resultados correctos para los materiales con turbidez menor y bajos para el material con turbidez mayor. Conclusiones. Los materiales de referencia utilizados han demostrado su utilidad para verificar los índices séricos de ictericia, hemólisis y lipidemia en los analizadores. Generalmente los índices proporcionados por los instrumentos concuerdan entre sí y con los valores asignados. Las diferencias más importantes entre analizadores se encuentran en el índice de lipidemia (AU)

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 (AU)

Harmonization in hemolysis detection and prevention. A working group of the Catalonian Health Institute (ICS) experience.

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.

Current status of verification practices in clinical biochemistry in Spain.

BACKGROUND: Verification uses logical algorithms to detect potential errors before laboratory results are released to the clinician. Even though verification is one of the main processes in all laboratories, there is a lack of standardization mainly in the algorithms used and the criteria and verification limits applied. A survey in clinical laboratories in Spain was conducted in order to assess the verification process, particularly the use of autoverification. METHODS: Questionnaires were sent to the laboratories involved in the External Quality Assurance Program organized by the Spanish Society of Clinical Biochemistry and Molecular Pathology. Seven common biochemical parameters were included (glucose, cholesterol, triglycerides, creatinine, potassium, calcium, and alanine aminotransferase). RESULTS: Completed questionnaires were received from 85 laboratories. Nearly all the laboratories reported using the following seven verification criteria: internal quality control, instrument warnings, sample deterioration, reference limits, clinical data, concordance between parameters, and verification of results. The use of all verification criteria varied according to the type of verification (automatic, technical, or medical). Verification limits for these parameters are similar to biological reference ranges. Delta Check was used in 24% of laboratories. Most laboratories (64%) reported using autoverification systems. Autoverification use was related to laboratory size, ownership, and type of laboratory information system, but amount of use (percentage of test autoverified) was not related to laboratory size. CONCLUSIONS: A total of 36% of Spanish laboratories do not use autoverification, despite the general implementation of laboratory information systems, most of them, with autoverification ability. Criteria and rules for seven routine biochemical tests were obtained.

Beyond proteinuria: VDR activation reduces renal inflammation in experimental diabetic nephropathy.

Local inflammation is thought to contribute to the progression of diabetic nephropathy. The vitamin D receptor (VDR) activator paricalcitol has an antiproteinuric effect in human diabetic nephropathy at high doses. We have explored potential anti-inflammatory effects of VDR activator doses that do not modulate proteinuria in an experimental model of diabetic nephropathy to gain insights into potential benefits of VDR activators in those patients whose proteinuria is not decreased by this therapy. The effect of calcitriol and paricalcitol on renal function, albuminuria, and renal inflammation was explored in a rat experimental model of diabetes induced by streptozotocin. Modulation of the expression of mediators of inflammation by these drugs was explored in cultured podocytes. At the doses used, neither calcitriol nor paricalcitol significantly modified renal function or reduced albuminuria in experimental diabetes. However, both drugs reduced the total kidney mRNA expression of IL-6, monocyte chemoattractant protein (MCP)-1, and IL-18. Immunohistochemistry showed that calcitriol and paricalcitol reduced MCP-1 and IL-6 in podocytes and tubular cells as well as glomerular infiltration by macrophages, glomerular cell NF-κB activation, apoptosis, and extracellular matrix deposition. In cultured podocytes, paricalcitol and calcitriol at concentrations in the physiological and clinically significant range prevented the increase in MCP-1, IL-6, renin, and fibronectin mRNA expression and the secretion of MCP-1 to the culture media induced by high glucose. In conclusion, in experimental diabetic nephropathy VDR activation has local renal anti-inflammatory effects that can be observed even when proteinuria is not decreased. This may be ascribed to decreased inflammatory responses of intrinsic renal cells, including podocytes, to high glucose.

Quality indicators and specifications for key analytical-extranalytical processes in the clinical laboratory. Five years' experience using the Six Sigma concept.

BACKGROUND: The results of 5 years of experience (2004-2008) with process-based quality management using quality indicators for key laboratory processes (analytic and extra-analytic) in a group of clinical laboratories affiliated with the Catalan Health Institute are presented. Our purpose was to analyze the evolution of the indicators, identify processes that require corrective measures, and obtain specifications that are more robust than the preliminary ones proposed in a previous study by the same group. METHODS: The yearly average was recorded for each indicator in each laboratory, the yearly interlaboratory median was calculated, and the changes occurring were studied to determine their continuity in the 5-year period. For each indicator, the average of the yearly medians was calculated and the results transformed to the Six Sigma scale to estimate the degree of control over the related process. It was suggested to establish the yearly interlaboratory median as the desirable specification for each indicator. RESULTS: The medians for most indicators were stable during the period studied. Thus, the specifications proposed in the first study were considered robust in these cases. The Six Sigma statistic provided added value in this study because it enabled detection of processes that should be improved, in which case the specifications proposed were considered provisional despite their stability. After identifying processes that have the greatest impact on patient safety, the group set a specification of 0%, regardless of the actual specification obtained, although the members are conscious of the difficulty in attaining this level of quality. Certain processes that are in a period of change obtained specifications that are considered in a phase of consolidation. CONCLUSIONS: The results for indicators related with sample collection indicate that the process is stable and well controlled. However, based on the results for Hemolyzed serum sample, the group saw the need for installing centrifuges in all phlebotomy centers and established a recommendation to unify the system for measuring hemolysis. The indicator External control exceeds acceptance limit clearly highlighted the need to rigorously monitor the analytic phase of the clinical laboratory. The values obtained for the indicator Reports from referred tests exceed delivery time show that there is considerable deviation regarding the expected report delivery time, whereas for in-house laboratory reports, delivery time is satisfactory.

Sustained activation of renal N-methyl-D-aspartate receptors decreases vitamin D synthesis: a possible role for glutamate on the onset of secondary HPT.

N-methyl-D-aspartate (NMDA) receptors (NMDAR) are tetrameric amino acid receptors that act as membrane calcium channels. The presence of the receptor has been detected in the principal organs responsible for calcium homeostasis (kidney, bone, and parathyroid gland), pointing to a possible role in mineral metabolism. The aim of this study was to test the effect of NMDAR activation in the kidney and on 1,25(OH)2D3 synthesis. We determined the presence of NMDAR subunits in HK-2 (human kidney cells) cells and proved its functionality. NMDA treatment for 4 days induced a decrease in 1α-hydroxylase levels and 1,25(OH)2D3 synthesis through the activation of the MAPK/ERK pathway in HK-2 cells. In vivo administration of NMDA for 4 days also caused a decrease in blood 1,25(OH)2D3 levels in healthy animals and an increase in blood PTH levels. This increase in PTH induced a decrease in the urinary excretion of calcium and an increase in urinary excretion of phosphorous and sodium as well as in diuresis. Bone turnover markers also increased. Animals with 5/6 nephrectomy showed low levels of renal 1α-hydroxylase as well as high levels of renal glutamate compared with healthy animals. In conclusion, NMDAR activation in the kidney causes a decrease in 1,25(OH)2D3 synthesis, which induces an increase on PTH synthesis and release. In animals with chronic kidney disease, high renal levels of glutamate could be involved in the downregulation of 1α-hydroxylase expression.

Indicators and quality specifications for strategic and support processes related to the clinical laboratory: four years' experience.

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.

N-methyl-D-aspartate receptors are expressed in rat parathyroid gland and regulate PTH secretion.

N-methyl-d-aspartate receptors (NMDAR) are tetrameric amino acid receptors which act as membrane calcium channels. The presence of the receptor has been detected in the principal organs responsible for calcium homeostasis (kidney and bone), pointing to a possible role in mineral metabolism. In the present work, the presence of the receptor was determined in normal parathyroid glands (PTG) by real-time PCR, immunoprecipitation, and immunohistrochemistry. Healthy animals showed a decrease in blood parathyroid hormone (PTH) levels 15 min after the treatment with NMDA. This effect was also observed in animals with high levels of PTH-induced EDTA injection, but not in uremic animals with secondary hyperparathyroidism (2HPT). Normal rat PTG incubated in media with low calcium concentration (0.8 mM CaCl2) showed a decrease in PTH release when NMDA was added to the media. This effect of NMDA was abolished when glands were coincubated with MK801 (a pharmacological blocker of the NMDA channel) or PD98059 (an inhibitor of the ERK-MAPK pathway). Glands obtained from animals with 2HPT showed no effect of NMDA in the in vitro release of PTH, together with a decrease in the expression of NMDAR1. In conclusion, NMDA receptor is present in PTG and is involved in the regulation of the PTH release. The mechanism by which NMDAR exerts its function is through the activation of the MAPK cascade. In uremic 2HPT animals the receptor expression is downregulated and the treatment with NMDA does not affect PTH secretion.

Quality indicators and specifications for strategic and support processes in laboratory medicine.

BACKGROUND: This work is the second part of a study regarding indicators and quality specifications for the non-analytical processes in laboratory medicine. Five primary care and five hospital laboratories agreed on the indicators for two strategic processes (quality planning and project development) and various support processes (client relationships, instrument and infrastructure maintenance, safety and risk prevention, purchases and storage, personnel training). METHODS: In the majority of cases, the median values recorded over 1 year is considered to be the state-of-the-art in our setting and proposed as the quality specification for the indicators stated. Values have been stratified according to primary care and hospital laboratory for referred tests and group of personnel for training. In some cases, the specifications have been set equal to zero events, such as serious incidents in the infrastructure maintenance process and number of work accidents in the safety and risk prevention process. RESULTS AND CONCLUSIONS: In light of this study, an effort is needed to optimize decisions regarding corrective actions and to move from a subjective individual criterion to systematic and comparative management. This preliminary study provides a comprehensive vision of a subject that could motivate further research and advances in the quality of laboratory services.