Quality assurance of add-on testing in plasma samples: stability limit for 29 biochemical analytes.

Introduction: Clinical laboratories should guarantee sample stability in specific storage conditions for further analysis. The aim of this study is to evaluate the stability of plasma samples under refrigeration for 29 common biochemical analytes usually ordered within an emergency context, in order to determine the maximum allowable period for conducting add-on testing. Materials and methods: A total of 20 patient samples were collected in lithium heparin tubes without gel separator. All analyses were performed using Alinity systems (Abbott Laboratories, Abbott Park, USA) and samples were stored at 2-8 °C. Measurements were conducted in primary plasma tubes at specific time points up to 48 hours, with an additional stability study in plasma aliquots extending the time storage up to 96 hours. The stability limit was estimated considering the total limit of change criteria. Results: Of the 29 studied parameters, 24 demonstrated stabilities within a 48-hour storage period in primary plasma tubes. However, five analytes: aspartate aminotransferase, glucose, lactate dehydrogenase, inorganic phosphate and potassium evidenced instability at different time points (7.9 hours, 2.7 hours, 2.9 hours, 6.2 hours and 4.7 hours, respectively). The stability study in plasma aliquots showed that all parameters remained stable for 96 hours, except lactate dehydrogenase, with a stability limit of 63 hours. Conclusions: A reduced stability of primary plasma samples was observed for five common biochemical analytes ordered in an emergency context. To ensure the quality of add-on testing for these samples, plasma aliquots provide stability for a longer period.

Periodic verification of results' comparability between several analyzers: experience in the application of the EP31-A-IR guideline.

OBJECTIVES: To assess the usefulness of the EP31-A-IR guideline published by the Clinical and Laboratory Standards Institute (CLSI) to perform the periodic verification of results' comparability between several analyzers. METHODS: Twenty-four biochemistry parameters that could be measured in different analyzers were included: albumin, alkaline phosphatase, alanine aminotransferase, amylase, aspartate aminotransferase, calcium, chloride, C-reactive protein, creatine kinase, creatinine, direct bilirubin, gamma glutamyl transferase, glucose, lactate dehydrogenase, magnesium, phosphate, potassium, sodium, total bilirubin, total cholesterol, total protein, triglycerides, urea and uric acid. In accordance with the EP31-A-IR guideline: (1) Patient samples were selected considering the concentration or activity of interest. (2) Acceptance criteria were established specifically for each concentration or activity level. A quality specification based on biological variation or on state of the art was selected, considering the analytical performance of the available technology. (3) Maximum allowable differences (MAD) between analyzers were calculated. (4) Measurements were performed as stated in appendix B of the guideline. (5) Maximum differences between analyzers were calculated. Results were considered comparable when the maximum difference was less than or equal to the MAD. RESULTS: For the 24 parameters evaluated, any difference between analyzers exceeded the MAD. CONCLUSIONS: The EP31-A-IR guideline proved to be useful for periodic verification of results' comparability. However, it must be considered that, to be practicable, it may require to adjust the acceptance criteria in accordance to the analytical performance of the available technology; as well as the number of analytical measurements conforming to the laboratory resources.

A Mediterranean Diet with an Enhanced Consumption of Extra Virgin Olive Oil and Pistachios Improves Pregnancy Outcomes in Women Without Gestational Diabetes Mellitus: A Sub-Analysis of the St. Carlos Gestational Diabetes Mellitus Prevention Study.

AIMS: The aim of the study was to evaluate the effect of a Mediterranean diet (MedDiet), enhanced with extra virgin olive oil (EVOO) and nuts, on a composite of adverse maternofoetal outcomes of women with normoglycemia during pregnancy. METHODS: This was a sub-analysis of the St Carlos gestational diabetes mellitus Prevention Study. Only normoglycemic women were analysed (697). They were randomized (at 8-12th gestational weeks) to: standard-care control group (337), where fat consumption was limited to 30% of total caloric intake; or intervention group (360), where a MedDiet, enhanced with EVOO and pistachios (40-42% fats of total caloric intake) was recommended. The primary outcome was a composite of maternofoetal outcomes (CMFOs): at least having 1 event of emergency C-section, perineal trauma, pregnancy-induced hypertension and preeclampsia, prematurity, large-for-gestational-age and small-for gestational-age. RESULTS: Crude relative risk showed that the intervention was associated with a significant reduction in the risk of CMFOs (0.48 [0.37-0.63]; p = 0.0001), with a number-needed-to-treat = 5. Risk of urinary tract infections, emergency C-sections, perineal trauma, large-for-gestational-age and small-for gestational age new-borns were also significantly reduced. CONCLUSION: A MedDiet, enhanced with EVOO and nuts, was associated with a risk reduction of CMFOs in over 50% in normoglycemic pregnant women. Therefore, it might be a potentially adequate diet for pregnant women. TRIAL REGISTRATION: Identifier ISRCTN84389045. The study was registered on September 27, 2013. Last edited on September 26, 2018.

A Mediterranean diet with additional extra virgin olive oil and pistachios reduces the incidence of gestational diabetes mellitus (GDM): A randomized controlled trial: The St. Carlos GDM prevention study.

BACKGROUND: Gestational diabetes mellitus (GDM) prevalence is increasing and becoming a major public health concern. Whether a Mediterranean diet can help prevent GDM in unselected pregnant women has yet to be studied. METHODS: We conducted a prospective, randomized controlled trial to evaluate the incidence of GDM with two different dietary models. All consecutive normoglycemic (<92 mg/dL) pregnant women at 8-12 gestational weeks (GW) were assigned to Intervention Group (IG, n = 500): MedDiet supplemented with extra virgin olive oil (EVOO) and pistachios; or Control Group (CG, n = 500): standard diet with limited fat intake. Primary outcome was to assess the effect of the intervention on GDM incidence at 24-28 GW. Gestational weight gain (GWG), pregnancy-induced hypertension, caesarean section (CS), preterm delivery, perineal trauma, small and large for gestational age (SGA and LGA) and admissions to neonatal intensive care unit were also assessed. Analysis was by intention-to-treat. RESULTS: A total of 874 women completed the study (440/434, CG/IG). According to nutritional questionnaires and biomarker analysis, women in the IG had a good adherence to the intervention. 177/874 women were diagnosed with GDM, 103/440 (23.4%) in CG and 74/434(17.1%) in IG, p = 0.012. The crude relative risk (RR) for GDM was 0.73 (95% CI: 0.56-0.95; p = 0.020) IG vs CG and persisted after adjusted multivariable analysis, 0.75(95% CI: 0.57-0.98; p = 0.039). IG had also significantly reduced rates of insulin-treated GDM, prematurity, GWG at 24-28 and 36-38 GW, emergency CS, perineal trauma, and SGA and LGA newborns (all p<0.05). CONCLUSIONS: An early nutritional intervention with a supplemented MedDiet reduces the incidence of GDM and improves several maternal and neonatal outcomes.

A novel TP53 germline inframe deletion identified in a Spanish series of Li-fraumeni syndrome suspected families.

Li-Fraumeni syndrome (LFS) is an autosomal dominant, inherited tumor predisposition syndrome associated with heterozygous germline mutations in the TP53 gene. The molecular diagnosis of LFS is important to develop strategies for early detection and access to the genetic counseling. Our study evaluated germline TP53 mutations in Spanish families with a history suggestive of LFS. Germline TP53 alterations in 22 families with a history suggestive of LFS were evaluated by Sanger sequencing and multiplex ligation-dependent probe amplification. Loss of heterozygosity analysis and immunohistochemistry of the protein in the tumor were performed in order to evaluate the pathogenicity of a novel alteration detected. A total of seven TP53 mutations were detected, six point mutations (4 missense and 2 nonsense) and a novel inframe deletion. 93% of mutation carriers developed at least one malignancy (mainly breast cancer and sarcomas), with a mean age at diagnosis of the first tumor of 30.2 years. Two missense mutations acted as dominant-negative. The novel inframe mutation c.437_445del was located in the DNA-binding domain. This mutation segregated with cancer in the family, and both high expression of the protein and loss of the wild-type TP53 allele were detected in the tumor of the carrier. We have found a novel inframe deletion in TP53 that likely results in the loss of p53 function and acts in a non-dominant negative way, although further studies are necessary to clarify this issue. The identification of novel TP53 alterations is crucial for a personalized cancer-risk management of the Li-Fraumeni syndrome.

Quantification of Very Low Concentrations of Leukocyte Suspensions In Vitro by High-Frequency Ultrasound.

Accurate measurement of very low cerebrospinal fluid (CSF) white blood cell (WBC) concentration is key to the diagnosis of bacterial meningitis, lethal if not promptly treated. Here we show that high frequency ultrasound (HFUS) can detect CSF WBC in vitro in concentrations relevant to meningitis diagnosis with a much finer precision than gold standard manual counting in a Fuchs-Rosenthal chamber. WBC concentrations in a mock CSF model, in the range 0-50 WBC/µL, have been tested and compared to gold standard ground truth. In this range, excellent agreement (Cohen's kappa [κ] = 0.78-90) (Cohen 1960) was observed between HFUS and the gold standard method. The presented experimental set-up allowed us to detect WBC concentrations as low as 2 cells/µL. HFUS shows promise as a low-cost, reliable and automated technology to measure very low CSF WBC concentrations for the diagnosis of early meningitis.