MiniRead: A simple and inexpensive do-it-yourself device for multiple analyses of micro-organism growth kinetics.

Fitness in micro-organisms can be proxied by growth parameters on different media and/or temperatures. This is achieved by measuring optical density at 600 nm using a spectrophotometer, which measures the effect of absorbance and side scattering due to turbidity of cells suspensions. However, when growth kinetics must be monitored in many 96-well plates at the same time, buying several 96-channel spectrophotometers is often beyond budgets. The MiniRead device presented here is a simple and inexpensive do-it-yourself 96-well temperature-controlled turbidimeter designed to measure the interception of white light via absorption or side scattering through liquid culture medium. Turbidity is automatically recorded in each well at regular time intervals for up to several days or weeks. Output tabulated text files are recorded into a micro-SD memory card to be easily transferred to a computer. We propose also an R package which allows (1) to compute the nonlinear calibration curves required to convert raw readings into cell concentration values, and (2) to analyze growth kinetics output files to automatically estimate proxies of growth parameters such as lag time, maximum growth rate, or cell concentration at the plateau.

Evaluation of the BD Phoenix CPO detect panel for prediction of Ambler class carbapenemases.

Rapid detection of carbapenemases as a cause of resistance is beneficial for infection control and antimicrobial therapy. The BD Phoenix NMIC-502 panel and CPO detect test identifies presence of carbapenemases in Enterobacterales such as Klebsiella pneumoniae and assigns them to Ambler classes. To evaluate the performance of the CPO detect panel, we employed a European collection of 1222 K. pneumoniae including carbapenem non-susceptible and susceptible clinical isolates from 26 countries, for which draft genomes were available after Illumina sequencing and the presence of carbapenemase genes had been identified by ARIBA gene calling. The CPO panel detected 488 out of 494 carbapenemase-encoding isolates as positive and six as negative. One-hundred and two isolates were tested positive for carbapenemase in the absence of any carbapenemase gene. The CPO panel identified 229 out of 230 KPC-positive isolates as carbapenemase producing and classified 62 of these as class A enzyme. Similarly, the CPO panel correctly specified 167 of 182 as class D. Regarding metallo-beta-lactamases, the CPO panel assigned 78 of 90 MBL positive isolates to class B enzymes. The sensitivity of the CPO panel in detecting carbapenemase activity was 99.5%, 97.7% and 98.3% for class A, B and D enzymes, respectively. The sensitivity in assignation to Ambler class A, B and D was 27%, 86% and 91%, respectively. An overall sensitivity of 98.8% and specificity of 86% in unclassified detection of carbapenemases was observed, with frequent false positive detection of carbapenemase producing organisms, thus rendering further confirmatory tests necessary.

Complex coacervation of pea albumin-pectin and ovalbumin-pectin assessed by isothermal titration calorimeter and turbidimetry.

BACKGROUND: This study investigates the complexation of a pea albumin-rich fraction and ovalbumin with pectin of different degrees of esterification (DE) and blockiness (DB) as a function of pH and biopolymer mixing ratio by turbidimetric titration and isothermal titration calorimetry (ITC). RESULTS: Turbidimetric analysis found maximum complexation occurred at a mixing ratio of 4:1 for pea albumin with high methoxy pectin, 8:1 for pea albumin with low methoxy pectin, and 8:1 for ovalbumin with low methoxy pectin. In the case of ovalbumin with high methoxy pectin, interactions were very weak. The pectin with high levels of esterification and blockiness displayed greater interactions with the pea albumin in both turbidimetry and ITC. However, low methoxy pectin imparted better interactions with ovalbumin and displayed higher optical density values than high methoxy pectin. CONCLUSIONS: The current study indicated that the different thermodynamic parameters of PA-pectin complexes can be tuned by controlling the structural characteristics (DB, DE, and d-galacturonic acid) of the pectin. © 2020 Society of Chemical Industry.

Analytical validation of a quantitative method for therapeutic drug monitoring on the Alinity®c Abbott.

OBJECTIVE: The aim of this study was to evaluate the analytical performance of the Alinity®c Abbott compared to the Architect® immunoassay system for the determination of drugs having a narrow therapeutic index. METHODS: Valproic acid, amikacin, gentamicin, phenobarbital and vancomycin were analyzed using Particle-Enhanced Turbidimetric Inhibitor Immunoassay (Petinia), phenytoin and theophylline were analyzed using an immunoenzymatic method and a colorimetric method was performed to quantify lithium. The methods were validated according to the total error approach. Seven validation standards were analyzed in quintuplet during four days to establish the limits of the methods. Dilution integrity and interferences (hemolysis and high concentrations of bilirubin and lipids) were also tested. Depending on the analyte, the results obtained for twenty to forty patients on the Alinity® were compared to those obtained on the Architect®. RESULTS: The bias and the coefficients of variation for repeatability and for intermediate precision were lower than 15% for all drugs. Accuracy profiles were acceptable (acceptance limits fixed at 30%) in the validated ranges. The lower limits of quantification (LLOQ) were similar to those determined by Abbott except for gentamicin for which we determined a LLOQ at 1.22 mg/L while Abbott determined it at 0.5 mg/L. All assays diluted linear and analyte concentrations were not affected by interferences. Concentrations obtained for real samples on the Alinity®c are comparable to those obtained on the Architect®ci. CONCLUSIONS: The analytical validation of a method suitable for therapeutic drug monitoring of drugs on the Alinity®c meets the requirements of European Medicines Agency.

Turbidimetry and Dielectric Spectroscopy as Process Analytical Technologies for Mammalian and Insect Cell Cultures.

The production of biopharmaceuticals in cell culture involves stringent controls to ensure product safety and quality. To meet these requirements, quality by design principles must be applied during the development of cell culture processes so that quality is built into the product by understanding the manufacturing process. One key aspect is process analytical technology, in which comprehensive online monitoring is used to identify and control critical process parameters that affect critical quality attributes such as the product titer and purity. The application of industry-ready technologies such as turbidimetry and dielectric spectroscopy provides a deeper understanding of biological processes within the bioreactor and allows the physiological status of the cells to be monitored on a continuous basis. This in turn enables selective and targeted process controls to respond in an appropriate manner to process disturbances. This chapter outlines the principles of online dielectric spectroscopy and turbidimetry for the measurement of optical density as applied to mammalian and insect cells cultivated in stirred-tank bioreactors either in suspension or as adherent cells on microcarriers.

Use of High-Resolution Pressure Nephelometry To Measure Gas Vesicle Collapse as a Means of Determining Growth and Turgor Changes in Planktonic Cyanobacteria.

Previous work has demonstrated that the physical properties of intracellular bacterial gas vesicles (GVs) can be analyzed in vivo using pressure nephelometry. In analyzing the buoyant state of GV-containing cyanobacteria, hydrostatic pressure within a sample cell is increased in a stepwise manner, where the concomitant collapse of GVs due to pressure and the resultant decrease in suspended cells are detected by changes in nephelometric scattering. As the relative pressure at which GVs collapse is a function of turgor pressure and cellular osmotic gradients, pressure nephelometry is a powerful tool for assaying changes in metabolism that affect turgor, such as photosynthetic and osmoregulatory processes. We have developed an updated and automated pressure nephelometer that utilizes visible-infrared (Vis-IR) spectra to accurately quantify GV critical collapse pressure, critical collapse pressure distribution, and cell turgor pressure. Here, using the updated pressure nephelometer and axenic cultures of Microcystis aeruginosa PCC7806, we demonstrate that GV critical collapse pressure is stable during mid-exponential growth phase, introduce pressure-sensitive turbidity as a robust metric for the abundance of gas-vacuolate cyanobacteria, and demonstrate that pressure-sensitive turbidity is a more accurate proxy for abundance and growth than photopigment fluorescence. As cyanobacterium-dominated harmful algal bloom (cyanoHAB) formation is dependent on the constituent cells possessing gas vesicles, characterization of environmental cyanobacteria populations via pressure nephelometry is identified as an underutilized monitoring method. Applications of this instrument focus on physiological and ecological studies of cyanobacteria, for example, cyanoHAB dynamics and the drivers associated with cyanotoxin production in aquatic ecosystems.IMPORTANCE The increased prevalence of bloom-forming cyanobacteria and associated risk of exposure to cyanobacterial toxins through drinking water utilities and recreational waterways are growing public health concerns. Cost-effective, early-detection methodologies specific to cyanobacteria are crucial for mitigating these risks, with a gas vesicle-specific signal offering a number of benefits over photopigment fluorescence, including improved detection limits and discrimination against non-gas-vacuolate phototrophs. Here, we present a multiplexed instrument capable of quantifying the relative abundance of cyanobacteria based on the signal generated from the presence of intracellular gas vesicles specific to bloom-forming cyanobacteria. Additionally, as cell turgor can be measured in vivo via pressure nephelometry, the measurement furnishes information about the internal osmotic pressure of gas-vacuolate cyanobacteria, which relates to the metabolic state of the cell. Together these advances may improve routine waterway monitoring and the mitigation of human health threats due to cyanobacterial blooms.

Evaluation of the Alfred™ turbidity monitoring system (Alifax®) following sonication in the diagnosis of central venous catheter colonization.

The conventional diagnostic techniques for catheter colonization (CC) take at least 48 h to yield results. Therefore, new diagnostic procedures that speed up the time necessary for results are needed. Our main objective was to assess the efficacy of the combination of sonication, turbidity monitoring, and MALDI-TOF to detect CC and catheter-related bloodstream infection (C-RBSI). For 1 year, we assessed central venous catheter (CVC) tips that arrived at the microbiology laboratory from adult patients admitted to our institution. CVC tips were cut, inoculated into 2.5 ml of BHI, and sonicated for 1 min. The suspension was then processed using Gram stain, quantitative culture (gold standard), and preincubation on the Alfred™ system. We analyzed the validity values of our new diagnostic approach for prediction of CC and C-RBSI and compared them with those of the gold standard. We collected a total of 167 catheters, 33 (19.8%) of which were colonized. We confirmed 21 episodes of C-RBSI. The distribution of microorganisms in colonized CVCs was as follows: Gram-positive, 68.4%; Gram-negative, 5.3%; and yeasts, 26.3%. The validity values for CC and C-RBSI using the new procedure were as follows: S, 39.4%/61.9%; Sp, 100%/100%; PPV, 100%/100%; and NPV, 87.0%/94.8%. The combination of sonication with a pre-incubation period based on turbidity monitoring using the Alfred™ system followed by MALDI-TOF proved to be a useful tool that was faster than conventional culture for ruling out C-RBSI. Future studies are needed to assess the clinical and economic impact of this diagnostic approach.

The Observation and Analysis of Internal Quality Control of Cystatin C in China from 2014 to 2017.

BACKGROUND: This study observed and analyzed the internal quality control (IQC) of cystatin C (CysC) so that we can have overall knowledge about imprecision levels in Chinese medical laboratories. METHODS: Using the software developed by the National Center for Clinical Laboratories (NCCL), we can get the IQC information of CysC from 2014 to 2017. Then the proportion of laboratories meeting five quality specifications (pass rates) were calculated and the current CVs (coefficient of variation) were also compared among subgroups and years. RESULTS: We find that the current CVs between 2014 and 2017 show significant differences (p = 0.016) and the proportion of laboratories meeting the 1/3 TEa specification distributes randomly from 2014 to 2017 but all of them exceed 80 percent. When the optimum specification is applied, the pass rates all become very low and the distributions are wide spread (from 3.63% to 6.74%). Beckman, Roche, and Hitachi are mainstream analyzers, making up as much as 78% to 85% of all. We can see a significant difference of the pass rate between Beckman and Hitachi in 2014 (p = 0.005). The primary means of detecting CysC is particle-enhanced turbidimetric immunoassay (PETIA) which makes up 30.57% - 32.64% of detection methods. The good news is that the IQC practice has improved greatly from 2014 to 2017 in laboratories in China. CONCLUSIONS: Medical laboratories have made some progress in IQC from 2014 to 2017, but it is still not satisfactory. As a result, there is a long way to go to improve detection quality of laboratories in China.

Performance evaluation of serum IgG subclass quantification using a SPAPLUS turbidimetric analyzer and comparison with the BNII nephelometer.

IgG consists of four subclasses: IgG1, IgG2, IgG3, and IgG4. Changes in the serum concentration of each subclass reflect different clinical situations, and quantification of each subclass is important to assess patients' clinical states. Herein, we evaluated the analytical performance of the SPAPLUS turbidimetric analyzer (The Binding Site, Birmingham, UK) for IgG subclass. Precision, linearity, comparison with the BNII system (Siemens Healthineers, Erlangen, Germany), and reference interval were assessed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The repeatability and within-laboratory precision were within 5% for all IgG subclasses. The coefficient of determination (R2) was higher than 0.99 for the analytical measurement range in all IgG subclasses. Comparison between SPAPLUS and BNII revealed significant differences in IgG1, IgG3, and IgG4 (p < .0001). IgG1 and IgG4 values were lower in SPAPLUS than BNII. On the other hand, IgG3 values were higher in SPAPLUS than BNII. The SPAPLUS turbidimetric analyzer exhibited good analytical performance for quantification of four IgG subclasses. Because of the differences between SPAPLUS and BNII, follow-up test for disease monitoring should be performed with same instrument.

Accuracy of data buoys for measurement of cyanobacteria, chlorophyll, and turbidity in a large lake (Lake Erie, North America): implications for estimation of cyanobacterial bloom parameters from water quality sonde measurements.

Microcystin (MCY)-producing harmful cyanobacterial blooms (cHABs) are an annual occurrence in Lake Erie, and buoys equipped with water quality sondes have been deployed to help researchers and resource managers track cHABs. The objective of this study was to determine how well water quality sondes attached to buoys measure total algae and cyanobacterial biomass and water turbidity. Water samples were collected next to two data buoys in western Lake Erie (near Gibraltar Island and in the Sandusky subbasin) throughout summers 2015, 2016, and 2017 to determine correlations between buoy sonde data and water sample data. MCY and nutrient concentrations were also measured. Significant (P < 0.001) linear relationships (R2 > 0.75) occurred between cyanobacteria buoy and water sample data at the Gibraltar buoy, but not at the Sandusky buoy; however, the coefficients at the Gibraltar buoy differed significantly across years. There was a significant correlation between buoy and water sample total chlorophyll data at both buoys, but the coefficient varied considerably between buoys and among years. Total MCY concentrations at the Gibraltar buoy followed similar temporal patterns as buoy and water sample cyanobacterial biomass data, and the ratio of MCY to cyanobacteria-chlorophyll decreased with decreased ambient nitrate concentrations. These results suggest that buoy data are difficult to compare across time and space. Additionally, the inclusion of nitrate concentration data can lead to more robust predictions on the relative toxicity of blooms. Overall, deployed buoys with sondes that are routinely cleaned and calibrated can track relative cyanobacteria abundance and be used as an early warning system for potentially toxic blooms.

The potential role of a turbidimetric heart-type fatty acid-binding protein assay to aid in the interpretation of persistently elevated, non-changing, cardiac troponin I concentrations.

BACKGROUND: Elevated and non-changing high-sensitivity cardiac troponin (hs-cTn) concentrations may suggest a process other than acute injury, possibly due to chronic condition(s) causing the elevation, an analytical error/interference or the formation of macrocomplexes. Heart-type fatty acid binding protein (H-FABP) might be useful in this setting to identify the etiology of abnormally high and non-changing cTn concentrations which could aid clinical decision making in the hospital setting. METHODS: We analytically validated the H-FABP assay (Randox) on the Abbott ARICHTECTc8000 platform, testing imprecision, linearity, stability, and matrix comparison. Over the 2-month analytical validation; EDTA plasma samples from patients with a hospital visit with persistently elevated and stable cTnI concentrations (Abbott hs-cTnI≥52 ng/L or 2x99th percentile upper limit of normal (ULN = 26 ng/L) with change between results <20%) were collected and frozen (-20 °C). These samples were tested with the H-FABP assay, polyethylene glycol (PEG) precipitation, with the lowest estimated glomerular filtration rate (eGRF) during the hospital visit also obtained from these patients. RESULTS: The H-FABP assay was linear, with concentrations stable after 4 freeze/thaw cycles, up to 150 h at room temperature, and comparable between lithium heparin and EDTA plasma. During the validation there were 6 patients with eGFR ≥60 ml/min/1.73m2 identified (total population screened n = 917) with high and non-changing hs-cTnI concentrations. All 6 patients had H-FABP<2xULN; with 3 patients having a macrocomplex and a final diagnosis of not ACS. CONCLUSION: Testing of H-FABP in patients with an eGFR≥60 ml/min/1.73m2 with persistently high and stable cTn elevations may help to confirm prior cardiac injury or the presence of macrocomplexes as the source of these elevations.

Performance assessment of a portable nephelometer for outdoor particle mass measurement.

The availability of portable nephelometers has improved assessment of exposure to atmospheric particles at a high resolution regarding space and time. However, nephelometer performance has seldom been evaluated for outdoor measurements, especially in Chinese cities. During 37 days of measurements at four outdoor sites in Shanghai, we assessed a popular nephelometer called SidePak (TSI Inc., USA) for PM1.0, PM2.5 and PM10 mass measurements and compared them to US federal reference methods (FRMs) based on different measurement principles. The nephelometer showed high measurement precision and stability and was strongly correlated with FRMs, making it superior to the portable light scattering monitors reported in the past and thus indicating the maturity of this principle. The nephelometer measurements overestimated all those of FRMs by a factor of two, which is higher than in evaluations in other international cities. This overestimation showed a descending order for PM1.0 (2.9-fold), PM2.5 (2.2-fold) and PM10 (1.9-fold) relative to the FRMs of tapered element oscillating microbalance or beta attenuation combined with nephelometry, based on whole samples. Sites that are far from direct pollution sources showed very good agreement between the nephelometer and FRMs for PM2.5 mass measurements, while, by comparison, the roadside site showed a lower SidePak/FRM PM2.5 ratio, which is likely due to higher abundance of elemental carbon in roadside particles. Relative humidity (RH) was shown to be a key factor that distorted the measurement of the nephelometer. An empirical formula incorporating an RH adjustment developed to correct the nephelometer could produce a reasonable result, even across the various sites. This study demonstrates the great potential of the nephelometer for outdoor particle mass measurements, but for accurate and comparable data, a site-specific calibration is strongly recommended before using.

Factors related to Secchi depths and their stability over time as determined from a probability sample of US lakes.

A probabilistic sample of lakes in the 48 coterminous US lakes was made by the United States Environmental Protection Agency in the 2007 National Lakes Assessment. Because of the statistical design, the results of our analyses of Secchi depths (SD) apply to a population of 45,265 lakes. We found statistically significant differences in mean Secchi depths between natural (1.57 m) and man-made lakes (1.18 m). The most important variable correlated with SD was turbidity, an optical measure related to suspended particles in the water column. For most lakes, chlorophyll a was highly correlated with both turbidity and SD, but several lakes had more turbidity and lower SD than expected based on chlorophyll a alone, indicating that non-algal suspended solids were an important factor. On an ecoregion basis, the non-algal suspended solids in the lake waters were related to the average levels of suspended solids in streams located in that ecoregion, and the non-algal suspended solids were more important in man-made than natural lakes. Phosphorus and nitrogen were directly correlated with chlorophyll a and turbidity and inversely correlated with SD. Based on diatom-inferred Secchi depths for the tops and bottoms of sediment cores from lakes in Ecoregions VIII and VII (excluding lakes in Minnesota) representing 40% of the natural lakes in the US, there has been no decrease in water transparency in that population of lakes in the past 70 or more years when the US population increased by 134%. We do not have information to determine if the other 60% of lakes have or have not changed.

Analytical performances of Optilite® turbidimeter (The Binding Site): a new dedicated analyser for specific proteins determination.

We checked analytical performances of Optilite® analyser for immunoglobulins G, A, M, subclasses of IgG, free light chains of Ig (Freelite®) and complement's fractions using Binding Site reagents. CVs for repeteability and reproducibility showed very good results, respectively <3% and <10% for all tested parameters, in agreement with Ricos and SFBC recommendations. Comparisons with results obtained on BN™II (Siemens) or SPAPLUS ® (Binding site) analysers showed a good agreement (>83%) according to Bland and Altman analysis. Sample throughput with either a batch of Freelite® only or Freelite® and immunoglobulins showed a gain of total realisation time on Optilite® versus BN™II. Optilite® analyser performed automatic dilutions until result and antigen excess determination for parameters as Freelite® or IgG4. In terms of practicability, traceability and maintenance, Optilite® turbidimeter alone or connected to LIS via DataSite software is well adapted to specialized laboratory for proteins determinations.

Everolimus TDM using Thermo Fisher QMS immunoassay on Indiko, Beckman DxC, AU680, and AU5800 analyzers.

OBJECTIVES: Everolimus (EVR), a mTOR inhibitor immunosuppressant approved for renal, liver and cardiac transplants. This study established the appropriate TDM performances of the Thermo Scientific QMS EVR Assay by using the Beckman DxC, followed by comparison to the Thermo Scientific Indiko and a previously published LC-MS/MS assay, and Beckman AU680 and AU5800 analyzers. DESIGN AND METHODS: The study initially established acceptable linearity, precision and accuracy of the QMS EVR turbidimetric assay. Sample preparation was initiated by mixing patient whole blood with methanol and a precipitation reagent. Supernatant was transferred to sample cups. Drug in the supernatant and drug coated on microparticle compete for the limited number of antibody binding sites. If EVR is absent in the sample supernatant, EVR coated microparticles are agglutinated in the presence of antibody reagent. If EVR is present, agglutination is partially inhibited, depending on EVR concentration. Calibrators range was from 1.5 to 20ng/mL. Comparison studies data were analyzed by Deming Regression and Bland-Altman plots. RESULTS: Precision studies showed the following mean concentrations 4.00-4.72, 7.70-8.20 and 14.80-15.56ng/mL, and CVs of 3.1-8.7%, 3.4-8.9% and 2.6-4.4% respectively. Comparison of analyses of 107 de-identified transplant samples by three analyzers - Indiko, DxC and AU680 showed: EVR concentrations from <1.5 to 13.6ng/mL, slopes 1.000 to 1.076, intercepts -0.053 to 0.462, and R 0.945 to 0.981. Another series of comparison studies (n=104) of Indiko and AU680 with LC-MS/MS showed the following: slopes 1.035 to 1.086, intercepts -0.019 to -0.265, and R 0.924 to 0.980. 2013-2016 CAP survey results were acceptable. CONCLUSIONS: Based on the experience of the past 3.5years, Thermo Scientific QMS EVR Immunoassay using four different analyzers offered adequate limit of detection and acceptable accuracy and precision, suitable for monitoring renal and liver transplant recipients.

Assessment of Intrathecal Free Light Chain Synthesis: Comparison of Different Quantitative Methods with the Detection of Oligoclonal Free Light Chains by Isoelectric Focusing and Affinity-Mediated Immunoblotting.

OBJECTIVES: We aimed to compare various methods for free light chain (fLC) quantitation in cerebrospinal fluid (CSF) and serum and to determine whether quantitative CSF measurements could reliably predict intrathecal fLC synthesis. In addition, we wished to determine the relationship between free kappa and free lambda light chain concentrations in CSF and serum in various disease groups. METHODS: We analysed 166 paired CSF and serum samples by at least one of the following methods: turbidimetry (Freelite™, SPAPLUS), nephelometry (N Latex FLC™, BN ProSpec), and two different (commercially available and in-house developed) sandwich ELISAs. The results were compared with oligoclonal fLC detected by affinity-mediated immunoblotting after isoelectric focusing. RESULTS: Although the correlations between quantitative methods were good, both proportional and systematic differences were discerned. However, no major differences were observed in the prediction of positive oligoclonal fLC test. Surprisingly, CSF free kappa/free lambda light chain ratios were lower than those in serum in about 75% of samples with negative oligoclonal fLC test. In about a half of patients with multiple sclerosis and clinically isolated syndrome, profoundly increased free kappa/free lambda light chain ratios were found in the CSF. CONCLUSIONS: Our results show that using appropriate method-specific cut-offs, different methods of CSF fLC quantitation can be used for the prediction of intrathecal fLC synthesis. The reason for unexpectedly low free kappa/free lambda light chain ratios in normal CSFs remains to be elucidated. Whereas CSF free kappa light chain concentration is increased in most patients with multiple sclerosis and clinically isolated syndrome, CSF free lambda light chain values show large interindividual variability in these patients and should be investigated further for possible immunopathological and prognostic significance.

The Roche Immunoturbidimetric Albumin Method on Cobas c 501 Gives Higher Values Than the Abbott and Roche BCP Methods When Analyzing Patient Plasma Samples.

BACKGROUND: Serum/plasma albumin is an important and widely used laboratory marker and it is important that we measure albumin correctly without bias. We had indications that the immunoturbidimetric method on Cobas c 501 and the bromocresol purple (BCP) method on Architect 16000 differed, so we decided to study these methods more closely. METHOD: A total of 1,951 patient requests with albumin measured with both the Architect BCP and Cobas immunoturbidimetric methods were extracted from the laboratory system. A comparison with fresh plasma samples was also performed that included immunoturbidimetric and BCP methods on Cobas c 501 and analysis of the international protein calibrator ERM-DA470k/IFCC. RESULTS: The median difference between the Abbott BCP and Roche immunoturbidimetric methods was 3.3 g/l and the Roche method overestimated ERM-DA470k/IFCC by 2.2 g/l. The Roche immunoturbidimetric method gave higher values than the Roche BCP method: y = 1.111x - 0.739, R² = 0.971. CONCLUSION: The Roche immunoturbidimetric albumin method gives clearly higher values than the Abbott and Roche BCP methods when analyzing fresh patient samples. The differences between the two methods were similar at normal and low albumin levels.

The Hemo One Autoanalyzer for Glycated Hemoglobin Assay.

BACKGROUND: Glycated hemoglobin (HbA1c) is widely used as a clinical marker of long-term blood glucose concentration in patients with diabetes. The clinical laboratory plays a vital role in the diagnosis and management of diabetes. Many methods for the measurement of HbA1c have been developed based on different analytical principles, often causing discordant results. For this reason, the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) established a reference method for HbA1c assay, namely, high-performance liquid chromatography-mass spectrometry/capillary electrophoresis (HPLC-MS/CE). OBJECTIVE: In order to evaluate in parallel 2 different routine methods, namely, ion-exchange HPLC and immunoturbidimetry. METHODS: For our comparison study, we used the Tosoh G8 HPLC analyzer and the Hemo One autoanalyzer system to test 100 blood specimens for HbA1c concentration, the values of which ranged from 4.3% (23.5 mmol/mol) to 14.7% (137 mmol/mol). RESULTS: Concordance between HPLC and the immunoturbidimetric method revealed perfect agreement with a Kappa value of 0.828. CONCLUSIONS: Our results confirm the validity of the immunoturbidimetric method compared with the reference method. Our findings highlight that these 2 methods are equivalent for the diagnosis and therapeutic monitoring of diabetes.