The effect of cytosorb® application on kidney recovery in critically ill patients with severe rhabdomyolysis: a propensity score matching analysis.

Severe rhabdomyolysis frequently results in acute kidney injury (AKI) due to myoglobin accumulation with the need of kidney replacement therapy (KRT). The present study investigated whether the application of Cytosorb® (CS) led to an increased rate of kidney recovery in patients with KRT due to severe rhabdomyolysis. Adult patients with a myoglobin-concentration >10,000 ng/ml and KRT were included from 2014 to 2021. Exclusion criteria were chronic kidney disease and CS-treatment before study inclusion. Groups 1 and 2 were defined as KRT with and without CS, respectively. The primary outcome parameter was independence from KRT after 30 days. Propensity score (PS) matching was performed (predictors: myoglobin, SAPS-II, and age), and the chi2-test was used. 35 pairings could be matched (mean age: 57 vs. 56 years; mean myoglobin: 27,218 vs. 26,872 ng/ml; mean SAPS-II: 77 vs. 76). The probability of kidney recovery was significantly (p = .04) higher in group 1 (31.4 vs. 11.4%, mean difference: 20.0%, odds ratio (OR): 3.6). Considering patients who survived 30 days, kidney recovery was also significantly (p = .03) higher in patients treated with CS (61.1 vs. 23.5%, mean difference: 37.6%, OR: 5.1). In conclusion, the use of CS might positively affect renal recovery in patients with severe rhabdomyolysis. A prospective randomized controlled trial is needed to confirm this hypothesis.

Cerebrospinal fluid analysis in emergency patients with suspected infection of the central nervous system.

BACKGROUND AND PURPOSE: Meningitis and encephalitis are potentially life-threatening diseases that require fast and accurate diagnostics and therapy. The value of polymerase chain reaction (PCR) multiplex testing in clinical practice is still a matter of debate. This study aims to evaluate its benefits and limitations in emergency patients. METHODS: We assessed the value of a meningoencephalitis PCR array in the clinical routine of an emergency department. RESULTS: Of 1578 emergency patients who received a lumbar puncture, 43% received it for a clinically suspected central nervous system (CNS) infection. After initial workup for cerebrospinal fluid (CSF) cell count, protein and glucose, a CNS infection was still considered likely in 307 patients. In these patients, further microbiologic workup was performed. A total of 230 samples were examined by PCR and a pathogen was detected in 66 of these samples. In the case of a positive microbiologic result, a comparison between PCR array and standard method was available for 59 samples, which demonstrated an overcall agreement of 80% (n = 47/59). Of interest, exclusively array-positive results were observed for patients with meningitis found to be positive for Streptococcus pneumoniae; four out of five patients had been treated with antibiotics before the lumbar puncture. In samples with normal CSF cell count only two positive array results were obtained, both for human herpesvirus 6, and these were not clinically relevant. CONCLUSION: Our data suggest that the array substantially contributes to a detection of pathogens in patients with suspected CNS infection and seems of particular interest in patients with acute bacterial meningitis under empiric antibiotic treatment. In CSF samples with normal cell count, it might be dispensable.

Diminished Short- and Long-Term Antibody Response after SARS-CoV-2 Vaccination in Hemodialysis Patients.

Short-term studies have shown an attenuated immune response in hemodialysis patients after COVID-19-vaccination. The present study examines how antibody response is maintained after vaccination against SARS-CoV-2 in a large population of hemodialysis patients from six outpatient dialysis centers. We retrospectively assessed serum antibody levels against SARS-CoV-2 spike protein and nucleocapsid protein (electrochemiluminescence immunoassays, Roche Diagnostics) after COVID-19-vaccination in 298 hemodialysis and 103 non-dialysis patients (controls), comparing early and late antibody response. Compared to a non-dialysis cohort hemodialysis patients showed a favorable but profoundly lower early antibody response, which decreased substantially during follow-up measurement (median 6 months after vaccination). Significantly more hemodialysis patients had anti-SARS-CoV-2-S antibody titers below 100 U/mL (p < 0.001), which increased during follow-up from 23% to 45% but remained low in the control group (3% vs. 7%). In multivariate analysis, previous COVID-19 infections (p < 0.001) and female gender (p < 0.05) were significantly associated with higher early as well as late antibody vaccine response in hemodialysis patients, while there was a significant inverse correlation between patient age and systemic immunosuppression (p < 0.001). The early and late antibody responses were significantly higher in patients receiving vaccination after a SARS-CoV-2 infection compared to uninfected patients in both groups (p < 0.05). We also note that a higher titer after complete immunization positively affected late antibody response. The observation, that hemodialysis patients showed a significantly stronger decline of SARS-CoV-2 vaccination antibody titers within 6 months, compared to controls, supports the need for booster vaccinations to foster a stronger and more persistent antibody response.

Performance testing of four automated coagulation analyzers in a university hospital setting with focus on global coagulation assays.

INTRODUCTION: Several automated coagulation analyzers are available for laboratory use. In a university hospital central laboratory, we compared four different instruments. The results for global coagulation assays are presented here. METHODS: ACL TOP 750 CTS (Instrumentation Laboratory), Atellica COAG 360 (COAG 360), BCS XP (both Siemens Healthineers), and cobas t 711 (Roche Diagnostics) were compared. For inter-instrument comparison, five basic coagulation parameters were analyzed in 476 patient plasma samples. Additional assessments included precision testing using commercial control samples and plasma pools, analysis time for a defined set of samples, sample capacity testing, minimum required sample volumes, and detection quality for hemolytic, icteric, or lipemic (HIL) interferences. RESULTS: Good concordance between different instruments was evident from Bland-Altman plots and comparison of data from each instrument with the overall median (τ≥0.8). Shortest analysis times were found for BCS XP and COAG 360, COAG 360 revealed highest sample capacity. Observed required sample volumes were broadly in line with manufacturer specifications and varied according to instrument configurations. HIL detection differed between instruments and was best with ACL TOP 750 CTS. CONCLUSION: The four analyzers showed similarly high levels of concordance, although some variations were apparent. The most significant differences between the instruments were found in analysis times and sample capacity. Analyzer capabilities must be considered when selecting laboratory equipment and defining algorithms for clinical practice.

Isotope dilution LC-MS/MS quantification of the cystic fibrosis transmembrane conductance regulator (CFTR) modulators ivacaftor, lumacaftor, tezacaftor, elexacaftor, and their major metabolites in human serum.

OBJECTIVES: Cystic fibrosis (CF) transmembrane conductance regulator (CFTR) modulators have revolutionized the therapeutic landscape in CF treatment. These vital drugs are extensively metabolized via CYP3A, so caution must be exercised in multimodal CF therapy because of the risk of adverse drug interactions. Our goal was to develop a highly sensitive assay for the purpose of therapeutic drug monitoring (TDM) in diagnostic laboratories. METHODS: After protein precipitation, the CFTR modulators ivacaftor, lumacaftor, tezacaftor, elexacaftor, and their metabolites ivacaftor-M1, ivacaftor-M6, and tezacaftor-M1 were separated with a two-dimensional chromatography setup within 5 min, and quantified with stable isotope-labeled internal standards. The method was validated according to the European Medicines Agency (EMA) guideline on bioanalytical method validation and applied to CF patient samples. RESULTS: Inaccuracy was ≤7.0% and the imprecision coefficient of variation (CV) was ≤8.3% for all quality controls (QCs). The method consistently compensated for matrix effects, recovery, and process efficiency were 105-115 and 96.5-103%, respectively. Analysis of CF serum samples provided concentrations comparable to the pharmacokinetic profile data reported in the EMA assessment report for the triple combination therapy Kaftrio. CONCLUSIONS: We hereby present a robust and highly selective isotope dilution liquid chromatography tandem mass spectrometry (ID-LC-MS/MS) assay for the simultaneous quantification of the so far approved CFTR modulators and their metabolites in human serum. The assay is suitable for state-of-the-art pharmacovigilance of CFTR modulator therapy in CF patients, in order to maximize safety and efficacy, and also to establish dose-response relationships in clinical trials.

Antibody response to mRNA SARS-CoV-2 vaccines in haemodialysis patients.

BACKGROUND: Some studies have shown an attenuated immune response in haemodialysis patients after vaccination. The present study examines the humoral response after mRNA vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in a large population of haemodialysis patients from different outpatient dialysis centres. METHODS: We retrospectively assessed antibodies against SARS-CoV-2 spike protein and nucleocapsid protein (chemiluminescence immunoassays, Roche diagnostics) 3-6 weeks after the second mRNA vaccine dose in 179 maintenance haemodialysis and 70 non-dialysis patients (control cohort). Differences in anti-SARS-CoV-2 spike protein titers were statistically analysed with respect to patient-relevant factors, including age, gender, previous coronavirus disease 2019 (COVID-19) infection, systemic immunosuppressive therapy and time on dialysis. RESULTS: We found a favourable, but profoundly lower SARS-CoV-2 spike protein antibody response in comparison with a non-dialysis cohort (median 253.5 versus 1756 U/mL, P < 0.001). In multivariate analysis, previous COVID-19 infection (P < 0.001) and female gender were associated with a significantly higher vaccine response (P = 0.006) in haemodialysis patients, while there was a significant inverse correlation with increasing patient age and systemic immunosuppression (P < 0.001). There was no statistically significant correlation between the antibody titer and time on dialysis. Immune response in haemodialysis patients with a previous COVID-19 infection led to substantially higher antibody titers that were equal to those of vaccinated non-dialysis individuals with previous infection. CONCLUSION: We strongly argue in favour of regular antibody testing after COVID-19 vaccination in haemodialysis patients. Further studies should elucidate the utility of booster vaccinations to foster a stronger and persistent antibody response.

[Anticoagulation in intensive care medicine]. / Antikoagulation in der Intensivmedizin.

Critically ill patients are at high risk of hemostasis disorders, which can be associated with both an increased risk of bleeding and an increased risk of thromboembolic events. In the case of acute vascular events, specific therapy with drug anticoagulation or platelet aggregation inhibition is essential. In patients with pre-existing conditions, the appropriate continuation of anticoagulation during intensive care treatment is important. Furthermore, in everyday clinical practice, prophylaxis of thromboembolism as well as the question of potential therapeutic options in the treatment of sepsis and infection-triggered disorders of blood coagulation are important. Specific questions arise with the use of extracorporeal devices such as renal replacement and circulatory assist systems. A number of new anticoagulation and anti-platelet drugs have become available in recent years. Laboratory monitoring of anticoagulation is central. In this overview, current aspects of these topics are presented.

High-resolution serum proteome trajectories in COVID-19 reveal patient-specific seroconversion.

A deeper understanding of COVID-19 on human molecular pathophysiology is urgently needed as a foundation for the discovery of new biomarkers and therapeutic targets. Here we applied mass spectrometry (MS)-based proteomics to measure serum proteomes of COVID-19 patients and symptomatic, but PCR-negative controls, in a time-resolved manner. In 262 controls and 458 longitudinal samples of 31 patients, hospitalized for COVID-19, a remarkable 26% of proteins changed significantly. Bioinformatics analyses revealed co-regulated groups and shared biological functions. Proteins of the innate immune system such as CRP, SAA1, CD14, LBP, and LGALS3BP decreased early in the time course. Regulators of coagulation (APOH, FN1, HRG, KNG1, PLG) and lipid homeostasis (APOA1, APOC1, APOC2, APOC3, PON1) increased over the course of the disease. A global correlation map provides a system-wide functional association between proteins, biological processes, and clinical chemistry parameters. Importantly, five SARS-CoV-2 immunoassays against antibodies revealed excellent correlations with an extensive range of immunoglobulin regions, which were quantified by MS-based proteomics. The high-resolution profile of all immunoglobulin regions showed individual-specific differences and commonalities of potential pathophysiological relevance.

SARS-CoV-2 antibody immunoassays in serial samples reveal earlier seroconversion in acutely ill COVID-19 patients developing ARDS.

OBJECTIVES: During the COVID-19 pandemic, SARS-CoV-2 antibody testing has been suggested for (1) screening populations for disease prevalence, (2) diagnostics, and (3) guiding therapeutic applications. Here, we conducted a detailed clinical evaluation of four Anti-SARS-CoV-2 immunoassays in samples from acutely ill COVID-19 patients and in two negative cohorts. METHODS: 443 serum specimens from serial sampling of 29 COVID-19 patients were used to determine clinical sensitivities. Patients were stratified for the presence of acute respiratory distress syndrome (ARDS). Individual serum specimens from a pre-COVID-19 cohort of 238 healthy subjects and from a PCR-negative clinical cohort of 257 patients were used to determine clinical specificities. All samples were measured side-by-side with the Anti-SARS-CoV-2-ELISA (IgG), Anti-SARS-CoV-2-ELISA (IgA) and Anti-SARS-CoV-2-NCP-ELISA (IgG) (Euroimmun AG, Lübeck, Germany) and the Elecsys Anti-SARS-CoV-2 ECLIA (Roche Diagnostics International, Rotkreuz, Switzerland). RESULTS: Median seroconversion occurred earlier in ARDS patients (8-9 days) than in non-ARDS patients (11-17 days), except for EUR N-IgG. Rates of positivity and mean signal ratios in the ARDS group were significantly higher than in the non-ARDS group. Sensitivities between the four tested immunoassays were equivalent. In the set of negative samples, the specificity of the Anti-SARS-CoV-2-ELISA (IgA) was lower (93.9%) compared to all other assays (≥98.8%) and the specificity of Anti-SARS-CoV-2-NCP-ELISA (IgG) was lower (98.8%) than that of Elecsys Anti-SARS-CoV-2 (100%). CONCLUSIONS: Serial sampling in COVID-19 patients revealed earlier seroconversion and higher signal ratios of SARS-CoV-2 antibodies as a potential risk marker for the development of ARDS, suggesting a utility for antibody testing in acutely diseased patients.

The stressed vascular barrier and coagulation - The impact of key glycocalyx components on in vitro clot formation.

INTRODUCTION: A functional vascular barrier controlling leukocyte recruitment into the perivascular space relies on an intact endothelial glycocalyx (EGX). Critical disease states such as sepsis or trauma can induce massive shedding of EGX components into the blood stream. Previous studies have shown that high blood levels of EGX components are correlated with bleeding in patients. The mechanism behind that observation remains to be fully elucidated. MATERIAL AND METHODS: The EGX components syndecan-1 (S1), hyaluronic acid (HA) and heparan sulfate (HS) were added to blood samples of 10 healthy male volunteers separately in three distinct concentrations to mimic three severity levels of in vitro EGX shedding. We analyzed spiked blood samples for leukocyte derived reactive oxygen species (ROS) release as a measure for innate immune activation and evaluated the impact on coagulation using clinical standard coagulation tests (SCTs) as well as rotational thrombelastometry (ROTEM®). RESULTS: Whereas ROS formation by polymorphonuclear leukocytes (PMN) was unaltered by all three substances, high concentrations of HS showed prolonged aPTT and TT compared to controls and S1 or HA. Changes in ROTEM® were discrete and mostly within normal range of values but analyses showed a significant reduction of clot firmness and formation by all EGX components compared to controls. Furthermore, alterations by HA and HS were dose dependent. Only HS showed a heparin like effect supporting the findings of SCTs. CONCLUSIONS: All EGX components interfere with clot formation and strength. HS mimics heparin effects in ROTEM® that confirm detectable alterations of standard coagulation tests.

Multicenter evaluation of the cobas m 511 integrated hematology analyzer.

INTRODUCTION: The cobas m 511 integrated hematology analyzer conducts a complete blood count (CBC), white blood cell (WBC) differential, reticulocyte count, and nucleated red blood cell count using automated digital microscopy. This multicenter study validated the analytical performance of the cobas m 511 system. METHODS: Repeatability, reproducibility, carryover, mode-to-mode comparison, cytomorphology, WBC clinical sensitivity, and method comparison were analyzed at four clinical sites using residual whole blood clinical samples (n = 2546) and fresh whole blood from healthy volunteers (n = 480). For WBC clinical sensitivity, the cobas m 511 system automated CBC and WBC differential, system flags, cobas m 511 images, and stained cobas m 511 slides were compared with manual microscopy. Sysmex® XN analyzers were used for interinstrument method comparison. RESULTS: Repeatability and reproducibility results showed low variability. There was no significant sample carryover and no difference between open/closed modes. The overall percentage agreement of morphology assessments with manual microscopy (n = 163 samples) was 95.6% for cobas m 511 images and 95.7% for cobas m 511 slides. The sensitivity and specificity for detecting distributional and/or morphological abnormalities were 94.4% and 74.6% for cobas m 511 automated differential, and 95.9% and 73.3% for cobas m 511 image assessment, compared with a manual 400-cell reference differential (n = 439 samples). Some discordance was seen for monocytes and basophils. Correlations between cobas m 511 and Sysmex XN system data were very good (Pearson's R ≥ 0.95 for most CBC parameters). CONCLUSION: The cobas m 511 system performs robustly in the clinical laboratory and is suitable for routine clinical use.

Multicenter performance evaluation of a second generation cortisol assay.

BACKGROUND: Untreated disorders of the adrenocortical system, such as Cushing's or Addison's disease, can be fatal, and accurate quantification of a patient's cortisol levels is vital for diagnosis. The objective of this study was to assess the analytical performance of a new fully-automated Elecsys® Cortisol II assay (second generation) to measure cortisol levels in serum and saliva. METHODS: Four European investigational sites assessed the intermediate precision and reproducibility of the Cortisol II assay (Roche Diagnostics) under routine conditions. Method comparisons of the Cortisol II assay vs. liquid chromatography-tandem mass spectrometry (LC-MS/MS), the gold standard for cortisol measurement, were performed. Cortisol reference ranges from three US sites were determined using samples from self-reported healthy individuals. RESULTS: The coefficients of variation (CVs) for repeatability, intermediate precision, and reproducibility for serum samples were ≤2.6%, ≤5.8%, and ≤9.5%, respectively, and for saliva were ≤4.4% and ≤10.9%, and ≤11.4%, respectively. Agreement between the Cortisol II assay and LC-MS/MS in serum samples was close, with a slope of 1.02 and an intercept of 4.473 nmol/L. Reference range samples were collected from healthy individuals (n=300) and serum morning cortisol concentrations (5-95th percentile) were 166.1-507 nmol/L and afternoon concentrations were 73.8-291 nmol/L. Morning, afternoon, and midnight saliva concentrations (95th percentile) were 20.3, 6.94, and 7.56 nmol/L, respectively. CONCLUSIONS: The Cortisol II assay had good precision over the entire measuring range and had excellent agreement with LC-MS/MS. This test was found suitable for routine diagnostic application and will be valuable for the diagnosis of adrenocortical diseases.

Ferromagnetic particles as a rapid and robust sample preparation for the absolute quantification of seven eicosanoids in human plasma by UHPLC-MS/MS.

We used ferromagnetic particles as a novel technique to deproteinize plasma samples prior to quantitative UHPLC-MS/MS analysis of seven eicosanoids [thromboxane B2 (TXB2), prostaglandin E2 (PGE2), PGD2, 5-hydroxyeicosatetraenoic acid (5-HETE), 11-HETE, 12-HETE, arachidonic acid (AA)]. A combination of ferromagnetic particle enhanced deproteination and subsequent on-line solid phase extraction (on-line SPE) realized quick and convenient semi-automated sample preparation-in contrast to widely used manual SPE techniques which are rather laborious and therefore impede the investigation of AA metabolism in larger patient cohorts. Method evaluation was performed according to a protocol based on the EMA guideline for bioanalytical method validation, modified for endogenous compounds. Calibrators were prepared in ethanol. The calibration curves were found to be linear in a range of 0.1-80ngmL(-1) (TXB2, PGE2, PGD2), 0.05-40ngmL(-1) (5-HETE, 11-HETE), 0.5-400ngmL(-1) (12-HETE) and 25-9800ngmL(-1) (AA). Regarding all analytes and all quality controls, the resulting precision data (inter-assay 2.6 %-15.5 %; intra-assay 2.5 %-15.1 %, expressed as variation coefficient) as well as the accuracy results (inter-assay 93.3 %-125 %; intra-assay 91.7 %-114 %) were adequate. Further experiments addressing matrix effect, recovery and robustness, yielded also very satisfying results. As a proof of principle, the newly developed LC-MS/MS assay was employed to determine the capacity of AA metabolite release after whole blood stimulation in healthy blood donors. For this purpose, whole blood specimens of 5 healthy blood donors were analyzed at baseline and after a lipopolysaccharide (LPS) induced blood cell activation. In several baseline samples some eicosanoids levels were below the Lower Limit of Quantification. However, in the stimulated samples all chosen eicosanoids (except PGD2) could be quantified. These results, in context with those obtained in validation, demonstrate the applicability of ferromagnetic particles for the sample preparation for eicosanoids in human plasma. Thus, we conclude that ferromagnetic particle enhanced deproteination is a promising novel tool for sample preparation in LC-MS/MS, which is of particular interest for automation in clinical mass spectrometry, e.g. in order to further address eicosanoid analysis in larger patient cohorts.

Comparison of five automated hematology analyzers in a university hospital setting: Abbott Cell-Dyn Sapphire, Beckman Coulter DxH 800, Siemens Advia 2120i, Sysmex XE-5000, and Sysmex XN-2000.

BACKGROUND: Various types of automated hematology analyzers are used in clinical laboratories. Here, we performed a side-by-side comparison of five current top of the range routine hematology analyzers in the setting of a university hospital central laboratory. METHODS: Complete blood counts (CBC), differentials, reticulocyte and nucleated red blood cell (NRBC) counts of 349 patient samples, randomly taken out of routine diagnostics, were analyzed with Cell-Dyn Sapphire (Abbott), DxH 800 (Beckman Coulter), Advia 2120i (Siemens), XE-5000 and XN-2000 (Sysmex). Inter-instrument comparison of CBCs including reticulocyte and NRBC counts and investigation of flagging quality in relation to microscopy were performed with the complete set of samples. Inter-instrument comparison of five-part differential was performed using samples without atypical cells in blood smear (n=292). Automated five-part differentials and NRBCs were additionally compared with microscopy. RESULTS: The five analyzers showed a good concordance for basic blood count parameters. Correlations between instruments were less well for reticulocyte counts, NRBCs, and differentials. The poorest concordance for NRBCs with microscopy was observed for Advia 2120i (Kendall's τb=0.37). The highest flagging sensitivity for blasts was observed for XN-2000 (97% compared to 65%-76% for other analyzers), whereas overall specificity was comparable between different instruments. CONCLUSIONS: To the best of our knowledge, this is the most comprehensive side-by-side comparison of five current top of the range routine hematology analyzers. Variable analyzer quality and parameter specific limitations must be considered in defining laboratory algorithms in clinical practice.

Analytical performance and diagnostic potential of immunoassays determining intact immunoglobulin kappa/lambda ratios in monoclonal gammopathies.

BACKGROUND: Hevylite chain (HLC) assays with specificity for epitopes at the junction between heavy and light chains of intact immunoglobulins (Ig) allow quantification of Ig kappa/lambda ratios of the three major Ig classes. Calculated Ig kappa/lambda ratios outside the reference range indicate a monoclonal background. The primary aim of the present study was to analytically validate HLC assays and to investigate their diagnostic potential in relation to immunofixation electrophoresis (IFE) as the standard method for identification of monoclonal proteins (MPs). A second aim was to investigate the diagnostic potential of HLC assays in disease monitoring. METHODS: Precision, linearity, accuracy, sensitivity, and specificity of HLC assays for Ig classes A, G, and M were determined as parameters of analytical performance. The diagnostic performance of HLC assays in the detection of MPs was investigated in patient sera revealing monoclonal bands in IFE (n = 156). The utility of the assays in disease monitoring was investigated in a proof of principal approach by quantification of HLC ratios in subsequent sera from stem cell transplanted (ScTx) myeloma patients (n = 4). RESULTS: All six HLC assays revealed analytical performances suitable for application in routine diagnostics. With regard to diagnostic performance, all samples with IgA MPs in IFE (n = 54) could be identified in the HLC IgA assay. Of sera showing IgG MP in IFE (n = 69), 57 could be identified in the HLC IgG assay, whereas 12 had normal IgG kappa/lambda ratios. Of sera showing IgM MP in IFE (n = 26), 25 could be identified in the HLC IgM assay, 1 serum revealed a normal IgM kappa/lambda ratio. ScTx patients achieving IFE-negative remission had normal HLC ratios. Those who failed to achieve IFE-negative remission showed normalization of conventional monitoring parameters but revealed HLC ratios never reaching reference range. CONCLUSIONS: HLC assays exhibit analytical performances suitable for clinical routine application. Our preliminary data from ScTx patients suggest a diagnostic potential especially of HLC IgA assay in disease monitoring. Other than that, combined application of HLC assays does not represent an alternative to IFE in first line diagnostics, in particular due to the limited diagnostic performance of the HLC IgG assay.

Variability of linezolid concentrations after standard dosing in critically ill patients: a prospective observational study.

INTRODUCTION: Severe infections in intensive care patients show high morbidity and mortality rates. Linezolid is an antimicrobial drug frequently used in critically ill patients. Recent data indicates that there might be high variability of linezolid serum concentrations in intensive care patients receiving standard doses. This study was aimed to evaluate whether standard dosing of linezolid leads to therapeutic serum concentrations in critically ill patients. METHODS: In this prospective observational study, 30 critically ill adult patients with suspected infections received standard dosing of 600 mg linezolid intravenously twice a day. Over 4 days, multiple serum samples were obtained from each patient, in order to determine the linezolid concentrations by liquid chromatography tandem mass spectrometry. RESULTS: A high variability of serum linezolid concentrations was observed (range of area under the linezolid concentration time curve over 24 hours (AUC24) 50.1 to 453.9 mg/L, median 143.3 mg*h/L; range of trough concentrations (Cmin) < 0.13 to 14.49 mg/L, median 2.06 mg/L). Furthermore, potentially subtherapeutic linezolid concentrations over 24 hours and at single time points (defined according to the literature as AUC24 < 200 mg*h/L and Cmin < 2 mg/L) were observed for 63% and 50% of the patients, respectively. Finally, potentially toxic levels (defined as AUC24 > 400 mg*h/L and Cmin > 10 mg/L) were observed for 7 of the patients. CONCLUSIONS: A high variability of linezolid serum concentrations with a substantial percentage of potentially subtherapeutic levels was observed in intensive care patients. The findings suggest that therapeutic drug monitoring of linezolid might be helpful for adequate dosing of linezolid in critically ill patients. TRIAL REGISTRATION: Clinicaltrials.gov NCT01793012. Registered 24 January 2013.

Effect of biobanking conditions on short-term stability of biomarkers in human serum and plasma.

BACKGROUND: Liquid biobanking is an important tool for laboratory diagnostics in routine settings and clinical studies. However, the current knowledge about adequate storage conditions for different classes of biomarkers is incomplete and, in part, contradictory. Here, we performed a comprehensive study on the effects of different storage conditions on the stability of various biomarkers in human serum and plasma. METHODS: Serum and citrated plasma were aliquoted and stored at 4 °C, -20 °C, -80 °C, and <-130 °C for 0, 7, 30, and 90 days, respectively (5-10 pools/condition). Additionally, frozen aliquots were temporarily exposed to higher temperatures during storage to simulate removing individual samples. Stability was tested for 32 biomarkers from 10 different parameter classes (electrolytes, enzymes, metabolites, inert proteins, complement factors, ketone bodies, hormones, cytokines, coagulation factors, and sterols). RESULTS: Biobanking at -80 °C and <-130 °C for up to 90 days did not lead to substantial changes (defined as >3 interassay coefficients of variation and p<0.01) of any biomarker concentration. In contrast, storage at 4 °C and -20 °C induced substantial changes in single biomarker concentrations in most classes. Such substantial changes were increases (<20%) in electrolytes, metabolites, and proteins, and decreases (<96%) in enzymes, ketone bodies, cytokines, and coagulation factors. Biomarker stability was minimally affected by occasional short-term thermal exposure. CONCLUSIONS: Based on these results, we provide recommendations for storage conditions of up to 90 days for several biomarkers. Generally, storage at ≤-80 °C for at least 90 days including occasional short-term thermal exposure is an excellent storage condition for most biomarkers.

Prevalence of symptomatic heart failure with reduced and with normal ejection fraction in an elderly general population-the CARLA study.

BACKGROUND/OBJECTIVES: Chronic heart failure (CHF) is one of the most important public health concerns in the industrialized world having increasing incidence and prevalence. Although there are several studies describing the prevalence of heart failure with reduced ejection fraction (HFREF) and heart failure with normal ejection fraction (HFNEF) in selected populations, there are few data regarding the prevalence and the determinants of symptomatic heart failure in the general population. METHODS: Cross-sectional data of a population-based German sample (1,779 subjects aged 45-83 years) were analyzed to determine the prevalence and determinants of chronic SHF and HFNEF defined according to the European Society of Cardiology using symptoms, echocardiography and serum NT-proBNP. Prevalence was age-standardized to the German population as of December 31st, 2005. RESULTS: The overall age-standardized prevalence of symptomatic CHF was 7.7% (95%CI 6.0-9.8) for men and 9.0% (95%CI 7.0-11.5) for women. The prevalence of CHF strongly increased with age from 3.0% among 45-54- year-old subjects to 22.0% among 75-83- year-old subjects. Symptomatic HFREF could be shown in 48% (n = 78), symptomatic HFNEF in 52% (n = 85) of subjects with CHF. The age-standardized prevalence of HFREF was 3.8 % (95%CI 2.4-5.8) for women and 4.6 % (95%CI 3.6-6.3) for men. The age-standardized prevalence of HFNEF for women and men was 5.1 % (95%CI 3.8-7.0) and 3.0 % (95%CI 2.1-4.5), respectively. Persons with CHF were more likely to have hypertension (PR = 3.4; 95%CI 1.6-7.3) or to have had a previous myocardial infarction (PR = 2.5, 95%CI 1.8-3.5). CONCLUSION: The prevalence of symptomatic CHF appears high in this population compared with other studies. While more women were affected by HFNEF than men, more male subjects suffered from HFREF. The high prevalence of symptomatic CHF seems likely to be mainly due to the high prevalence of cardiovascular risk factors in this population.