Performance characteristics of automated clinical chemistry analyzers using commercial assay reagents contributing to quality assurance and clinical decision in a hospital laboratory.

Background: Clinical laboratories provide essential diagnostic services that are essential in clinical decision making, contributing to the quality of healthcare. The performance of two Siemens ADVIA 1800 analyzers was characterized in a hospital Biochemistry laboratory in order to evaluate the analytical characteristics of such automated analyzer systems using nonoriginal assay reagents attempting to support laboratory quality service and crucial clinical decision making. Methods: We independently completed performance validation studies including trueness, precision, sensitivity as well as measurement of uncertainty and sigma metrics calculation for 25 biochemical parameters. Results: Trueness expressed as bias was less than 20% for both ADVIA 1800 analyzers. Within run and total precisions expressed as CV% were ≤9.85% on both analyzers for most parameters studied with few exceptions (Mg, TB, DB, Cl, HDL and UA) observed either in low or in high level samples and between the two analyzers. LoB, LoD and LoQ values produced by the two analyzers were comparable except Cl. Uncertainty values produced by the two analyzers were comparable with no significant differences. Quality performance of reagent assays was studied using the sigma metrics system. The sigma values were plotted on normalized method decision charts for graphical representation of assay performances for each analyzer. Conclusions: The two ADVIA systems, independently evaluated, showed consistent performance characteristics with certain discrepancies by several reagents. Sigma analysis was helpful for revealing the quality performance of non-original reagents supporting the need for strict assessment of quality assurance and in some instances optimization/improvement of assay methods.

Performance Evaluation of the Mindray BC 6800 Hematology Analyzer and Flag Comparison with the XE-2100 and Manual Microscopy.

BACKGROUND: The Mindray BC-6800 automated hematology analyzer is an automated hematology analyzer and 5-part leukocyte differential counter for in vitro diagnostic use in clinical laboratories. It is necessary to undergo an evaluation before the instrument is used to test patient samples. METHODS: The performance was evaluated with regards to precision, linearity, carry-over, and method comparison. The flag performances were evaluated and compared with the Sysmex XE-2100 hematology analyzer and manual microscope in the hematology laboratory of a tertiary hospital in China. RESULTS: There was minimal carryover (< 0.05%) and excellent linearity for white blood cells and platelet (PLT) counts (r > 0.999). The BC-6800 displayed very good correlation (r > 0.97) with the XE-2100 for blood cell count and cell differential parameters. In a comparison of 295 leukocyte differential count results analyzed in parallel with manual microscopy, the main flags (immature granulocytes, blasts, abnormal lymphocytes) showed approxi-mately the same sensitivity and specificity on both analyzers (sensitivity > 90%, specificity > 78%). CONCLUSIONS: The BC-6800 showed excellent performance and supplied confidence in flag information for abnormal samples in the routine hematology laboratory.

Performance Evaluation of an Enzyme-Linked Immunosorbent Assay for Seven Autoantibodies in Lung Cancer.

BACKGROUND: To verify and evaluate the performance characteristics of an enzyme-linked immunosorbent assay (ELISA) assay kit (Hangzhou Cancer probe Biotech Company) for seven autoantibodies (7-AABS), including p53, GAGE7, PGP9.5, CAGE, MAGEA1, SOX2, and GBU4-5. METHODS: Evaluation was carried out according to "Guidelines for performance evaluation of in vitro diagnostic reagent". The performance parameters included detection limit, reportable range, precision, accuracy, and method comparison. RESULTS: The detection limit was less than 3.75 U/mL. Reportable range was from 3.75 U/mL to 60 U/mL. The coefficient of variations (CVs) of within-run of 7-AABS were 5.15% - 10.13%, and between-run of CVs were 3.41% - 8.80%. For accuracy verification, the relative deviations (Bias) were all lower than 15% in the indicated concentration range. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and ac-curacy were 35.9%, 90.0%, 80.3%, 55.3%, 61.3%, respectively. CONCLUSIONS: Overall, the verification study demonstrated the performance of the kit meets the testing requirements. It is qualified for clinical applications.

Do Serum Creatinine Levels Show Clinically Significant Fluctuations on Serial Determinations on the Siemens Advia 1800 Analyzer?

BACKGROUND: The goal of this work was to determine whether there are clinically significant fluctuations in the level of serum creatinine on serial determinations, especially in the borderline range (1.1-1.3 mg/dl), after specimen storage. METHODS: Sixty-one serum samples were analyzed. They were divided into three categories based on the initial serum creatinine measurement: low (≤1.0 mg/dl), borderline (1.1-1.3 mg/dl), and high (≥1.4 mg/dl). The specimens were stored at 4°C and run on the Siemens Advia 1800 chemistry analyzer on days 1, 3, and 11. RESULTS: Statistical comparisons of the three groups were made using the unpaired t-test, yielding a two-tailed P-value for each group comparison. The P-values ranged from 0.0829 to 0.3892, indicating no statistically significant difference between the standard deviations of each group. CONCLUSIONS: Mild-to-moderate fluctuations in precision occur in successive serum creatinine determinations. The overwhelming majority of these fluctuations should not affect clinical decision making.

Medical Devices; Clinical Chemistry and Clinical Toxicology Devices; Classification of the Organophosphate Test System. Final order.

The Food and Drug Administration (FDA or we) is classifying the organophosphate test system into class II (special controls). The special controls that apply to the device type are identified in this order and will be part of the codified language for the organophosphate test system's classification. We are taking this action because we have determined that classifying the device into class II (special controls) will provide a reasonable assurance of safety and effectiveness of the device. We believe this action will also enhance patients' access to beneficial innovative devices, in part by reducing regulatory burdens.

Centrifugal microfluidic platforms: advanced unit operations and applications.

Centrifugal microfluidics has evolved into a mature technology. Several major diagnostic companies either have products on the market or are currently evaluating centrifugal microfluidics for product development. The fields of application are widespread and include clinical chemistry, immunodiagnostics and protein analysis, cell handling, molecular diagnostics, as well as food, water, and soil analysis. Nevertheless, new fluidic functions and applications that expand the possibilities of centrifugal microfluidics are being introduced at a high pace. In this review, we first present an up-to-date comprehensive overview of centrifugal microfluidic unit operations. Then, we introduce the term "process chain" to review how these unit operations can be combined for the automation of laboratory workflows. Such aggregation of basic functionalities enables efficient fluidic design at a higher level of integration. Furthermore, we analyze how novel, ground-breaking unit operations may foster the integration of more complex applications. Among these are the storage of pneumatic energy to realize complex switching sequences or to pump liquids radially inward, as well as the complete pre-storage and release of reagents. In this context, centrifugal microfluidics provides major advantages over other microfluidic actuation principles: the pulse-free inertial liquid propulsion provided by centrifugal microfluidics allows for closed fluidic systems that are free of any interfaces to external pumps. Processed volumes are easily scalable from nanoliters to milliliters. Volume forces can be adjusted by rotation and thus, even for very small volumes, surface forces may easily be overcome in the centrifugal gravity field which enables the efficient separation of nanoliter volumes from channels, chambers or sensor matrixes as well as the removal of any disturbing bubbles. In summary, centrifugal microfluidics takes advantage of a comprehensive set of fluidic unit operations such as liquid transport, metering, mixing and valving. The available unit operations cover the entire range of automated liquid handling requirements and enable efficient miniaturization, parallelization, and integration of assays.

Contactless conductivity detection for analytical techniques: developments from 2010 to 2012.

The developments in the field of capacitively coupled contactless conductivity detection in the approximate period from July 2010 to June 2012 are traced. Few reports concerning fundamental studies or new detector designs have appeared. On the other hand, applications in standard CZE are flourishing and contactless conductivity measurements are increasingly being employed as part of novel or more sophisticated experimental systems. Work on the lab-on-chip devices integrating contactless conductivity detection is continuing. A range of reports on the use of the simple yet powerful detection technique of contactless conductivity measurements in chromatographic separation as well as for analytical methods not including a separation step have also appeared.

Applications of monolithic solid-phase extraction in chromatography-based clinical chemistry assays.

Complex matrices, for example urine, serum, plasma, and whole blood, which are common in clinical chemistry testing, contain many non-analyte compounds that can interfere with either detection or in-source ionization in chromatography-based assays. To overcome this problem, analytes are extracted by protein precipitation, solid-phase extraction (SPE), and liquid-liquid extraction. With correct chemistry and well controlled material SPE may furnish clean specimens with consistent performance. Traditionally, SPE has been performed with particle-based adsorbents, but monolithic SPE is attracting increasing interest of clinical laboratories. Monoliths, solid pieces of stationary phase, have bimodal structures consisting of macropores, which enable passage of solvent, and mesopores, in which analytes are separated. This structure results in low back-pressure with separation capabilities similar to those of particle-based adsorbents. Monoliths also enable increased sample throughput, reduced solvent use, varied support formats, and/or automation. However, many of these monoliths are not commercially available. In this review, application of monoliths to purification of samples from humans before chromatography-based assays will be critically reviewed.

Calibration verification for Olympus and Hitachi automatic biochemistry analyzers using albumin.

BACKGROUND: The validity of calibration settings is confirmed by testing materials of known concentration in the same manner as patient specimens to assure the test system is accurate throughout the reportable range. CLIA'88 states calibration verification procedures are required to confirm the continued accuracy of the test system throughout the laboratory's reportable range of test results. METHODS: In accordance with the instruments used, the albumin data were divided into either the Olympus or the Hitachi groups. The performance of calibration verification was based on the approach of calibration verification currently used by the College of American Pathologists (CAP), i.e., the slope and intercept of the calibration line were tested by a one-sample t test, the percent difference was calculated and was compared with allowable error. RESULTS: In the Olympus group, verified 1, different 1, verified 2, and different 2 were 5.6%, 0%, 60.6%, and 33.8%, respectively. In the Hitachi group, verified 1, different 1, verified 2, and different 2 were 4.5%, 1.5%, 58.2%, and 35.8%, respectively. CONCLUSIONS: The method of calibration verification used by the CAP was reasonable and feasible. In this study, 64.5% of participating laboratories passed the evaluation of calibration verification for the Olympus and Hitachi analyzers using albumin.

Development of microscopic review criteria by comparison urine flow cytometer, strip and manual microscopic examination.

BACKGROUND: Microscopic examination is essential for urine analysis, but a time-consuming procedure. This study was undertaken to evaluate an automated urinalysis system - the Sysmex UF-1000i (URISYS 2400) for the analysis of urine constituents including chemistry components and particles. The objective was to screen urine samples and determine the screening criteria which would minimize the number of specimens reviewed with the microscope yet ensuring correct results. METHODS: A total of 1300 urine samples were sent for urinalysis using the automated system and compared with results obtained from manual microscopy using the Fuchs-Rosenthal counting chamber. RESULTS: Using Pearson statistics, we observed correlation between the UF-1000i and manual microscopy: for red blood cells (RBCs) r was 0.949, for white blood cells (WBCs) r was 0.882, for epithelial cells (EC) r was less than 0.76, for casts r was less than 0.7, while correlation between the URISYS 2400 and manual microscopy: for red blood cells r was 0.772 and for white blood cells r was 0.771. With the help of Uriaccess (an expert system provided by the Sysmex Corporation), 37 rules for microscopic review were set up. The review rules were validated, the review rate was less than 30% and the false-positive and false-negative results were acceptably low. CONCLUSIONS: UF-1000i is capable of reproducible measurement of urine particles within the clinically relevant range and shows its advantage over URISYS 2400. It is an optimal strategy for urine sample screening using the combination of the two methods.

Sample preparation for measurement of plasma mycophenolic acid concentrations using chromatographically functionalized magnetic micro-particles.

Utilizing chromatographically modified magnetic micro-particles is an innovative principle of sample preparation for quantitative analysis of small molecules in complex biomedical samples by liquid chromatography tandem mass spectrometry. Since no vacuum or pressure has to be applied-in contrast to cartridge based solid phase extraction protocols-the principle's main characteristics are potentially straightforward automation and a high extraction performance (in terms of µg of extraction material per µL of sample). Following first descriptions of the approach, this article reports, the validation of a magnetic particle-based, analytical method for the quantification of the immunosuppressant mycophenolic acid in plasma. This sample preparation technology has shown a good performance for this clinically relevant analyte. As a result, we conclude that further work towards the implementation of this technology in a multi- analyte approach on robotic systems, aiming towards a fully automated process, is justified.

Applications of monolithic columns in liquid chromatography-based clinical chemistry assays.

Monolithic columns have slowly been applied to HPLC methods for clinical chemistry testing in the last 10 years. The application areas include therapeutic drug monitoring, drugs of abuse, vitamins, porphyrins, and steroids. In comparison with conventional particulate columns, the monolithic columns may offer shorter chromatography time, more robustness, and better resolution for certain analytes. The potential drawback of large mobile phase consumption may be improved with smaller id columns, which are currently on the market. Methods covered in this review are those searchable in PubMed up to December 2010. This review highlights the emergence of monolithic column technology in HPLC methods used for clinical chemistry testing. The goals of this review are threefold: (i) To identify the areas of clinical chemistry that analytical monolithic columns have been used in HPLC methods. (ii) To demonstrate the application of analytical monolithic columns in HPLC methods using different detection systems. (iii) To discuss the advantages and limitations of the monolithic columns compared with particulate columns in the clinical chemistry applications.

Evaluation of the quick-clotting serum separator tube, VQ-Tube™, for clinical chemistry and thyroid hormone assays.

BACKGROUND: The type of blood collection tube affects specimen quality and laboratory results. Because plasma specimens have a shorter processing time compared with serum specimens, emergency biochemistry tests use plasma. However, serum specimens remain stable after centrifugation and show more accurate results than plasma. Therefore, a quick-clotting serum separator tube is expected to be useful for shorter turnaround times and accurate results. We evaluated a new quick-clotting serum separator tube VQ-Tube™ (AB Medical, Korea) for clinical chemistry and thyroid hormone assays. METHODS: One hundred volunteers from four university hospitals were recruited, and peripheral blood samples were collected in quick-clotting serum separator tube VQ-Tubes™ and the commonly used serum separator tube V-Tubes™. The obtained specimens were used for 16 clinical chemistry assays and three thyroid hormone assays. RESULTS: The differences (%) in the test results obtained from the samples in each tube satisfied the allowable difference ranges (19 assays). The differences in the test results between the tubes satisfied the desired specifications for accuracy except for the glucose results (2.75%). The paired t-test revealed significant differences between the results of six assays, but each set of results showed a good correlation. Samples were visually inspected for serum clarity and gel barrier integrity, and incomplete clotting reactions and haemolysed serum were not observed. CONCLUSIONS: The new quick-clotting VQ-Tube™ demonstrated reliable test results compared with the commonly used serum separator tube V-Tube™. This quick-clotting tube will provide fast test results with adequately separated serum specimens, especially for patients who need fast tests.

Centralization of multisite reagent lot-to-lot validation for Ortho Clinical Vitros chemistry instruments.

OBJECTIVE: Reagent lot-to-lot comparisons are recommended by accreditation bodies to ensure that the performance of each reagent lot meets acceptable standards for quality patient results. The general approach is comprised of performing quality control (QC) and patient comparison between the old and new reagent lots and evaluating against a pre-defined criteria. Reagent lot comparison practices are often variable despite using the same instrument across different laboratories. This is costly, time consuming, and can lead to variability in acceptance criteria. While Clinical & Laboratory Standards Institute (CLSI) has a recommended guideline for reagent lot validation, it is often difficult to execute for small and rural laboratories due to limited resources. Defining the analytes required for detailed validation is important to allocate appropriate resources to ensure quality patient results. The goal of this study was to develop a standardized approach to reagent lot validation and optimize lab resources on Vitros chemistry instruments. DESIGN AND METHOD: This study consists of a retrospective and prospective analysis of reagent lot changes in dry slide chemistry analyzers (Ortho Clinical Diagnostics Vitros). Two years of retrospective reagent lot comparison data was obtained at a single site. A prospective study was conducted by assessing aliquots of 10 patient sample pools at 9 sites with Vitros analyzers. RESULTS: Of the 19 chemistry analytes evaluated, albumin, sodium, and total protein showed significant differences between reagent lots and also exceeded the pre-defined acceptance criteria. CONCLUSION: For these analytes, our recommendations are to perform a comprehensive lot validation with QC and patient samples. A simple lot validation with a reflex approach comprised of initially assaying QC can be adapted for the more stable analytes to allow achieving quality patient result in a resource constraint rural environment.

[The metallic profile: a new biological concept]. / Une nouvelle approche biologique: le profil métallique.

Considerable advances have been made in metals and metalloids analysis over the past decade. This analysis is a basic stage in deficiency or toxicity assessment. A recently introduced technique, inductively coupled plasma mass spectrometry (ICP-MS) is progressively replacing atomic absorption. This analysis permits multi-elementary determinations, many ten or so elements, among periodic classification, with an optimal gain in sensitivity in many biological matrices: i.e. whole blood, plasma, urine, hair, nail, and biopsy samples. Moreover, this method allows semi-quantitative determination with an additional thirty supplementary elements, which enables the toxicologist to sufficiently estimate the toxic levels and metal exposure. The authors demonstrate that the ICP-MS could be very useful for a wide range of clinical applications. Furthermore, this procedure offers new exploration possibilities in various fields such as clinical chemistry but also clinical toxicology, forensic toxicology as well as workplace testing or environmental exposure and permits epidemiologic studies. This analytical method in fact also provides a new biologic approach. To our knowledge we are the first to propose the metallic profile.

Instrumentation in clinical chemistry.

Major advances in instrumentation have revolutionized the clinical chemistry laboratory during the past two decades. This article focuses on some of the more recent developments in instrumentation for clinical chemistry in the areas of general chemistry, immunoassays, urinalysis, electrophoresis, chromatography, and trace metal analyses.

Therapeutic drug monitoring and drugs of abuse testing on the cobas 6000 analyzer series: analytical performance under routine-like conditions.

BACKGROUND: The analytical performance of the clinical chemistry module c 501 (cobas 6000 analyzer series) was evaluated for therapeutic drug monitoring and drugs of abuse testing using a spectrum of representative assays. Particular attention was paid to potential interactions between reagents using a simulated routine workload. METHODS: Within-run and total imprecision were assessed using a selection of representative reagents. Deviation from a consensus mean was tested using samples from a proficiency testing scheme. Method comparison using routine samples was carried out against the MODULAR ANALYTICS SWA and COBAS INTEGRA 800 analysis systems. RESULTS: Total coefficients of variation (CV) ranged from 1.9% to 7.8% for individual drugs, and from 3.2% to 8.6% for drugs of abuse testing. Results from proficiency test samples were between 81% and 125% of the consensus mean for therapeutic drugs. Method comparisons (Passing-Bablok regression) showed overall good comparability to MODULAR ANALYTICS SWA and COBAS INTEGRA 800 systems, with slopes from 0.93 to 1.17 and correlation coefficients r > 0.98. Imprecision in a simulated routine run was tested using a total of 42 methods (10 therapeutic drug monitoring, 9 drugs of abuse testing, 3 enzymes, 12 substrates, 8 specific protein assays). Imprecision in the reference batch run ranged from 0.7% to 5.0% CV for therapeutic drug monitoring assays, except for digoxin (DIG) (7.3%), and from 0.9% to 7.7% for drugs of abuse testing. The CVs of general clinical chemistry and specific protein tests were within the expected limits of 2% and 4%. CV changes in the simulated routine run were within the expected limits for most assays. Negative DeltaCVs (> or = 2%) for DIG, digitoxin (DIGIT), cannabinoids (THC), and phencyclidine (PCP) may indicate improved performance when running these assays in a simulated routine operation. A positive DeltaCV (> or = 3%) was found for amphetamines (AMPHs). CONCLUSIONS: In conclusion, the cobas c 501 module seems to be well-suited for routine use as consolidated workstation. Except for a potential interaction with AMPH, as indicated by the positive DeltaCV, no significant interferences from different reagents could be observed during this study.

New method for calcium on the ADVIA analyzer is free from interference of gadolinium-type contrast agents.

Recently, Siemens Diagnostics released a new calcium assay (CA_2) based on complex formation of calcium with Arsenazo III dye for use on the three automated, random access ADVIA Chemistry analyzers (1650, 2400, and 1200). We evaluated this method for analytical performance as well as potential interference from gadolinium-containing magnetic contrast agents. With Siemens Chemistry serum and urine controls, 2-levels each, the imprecision for the new method was (n=40 each): within-run and total CV of <2.2 and <3.8%, respectively, over all three platforms. The analytical range/linearity of the method (all three systems) was 1-16 mg/dl (serum or plasma) and 1-32 mg/dl (urine). The new method on all three platforms correlated well with a reference (Inductively Coupled Plasma Atomic Emission Spectroscopy) method (n=61, range 4.03-10.30 mg/dl). The ADVIA 1650 CA_2 method also correlated well with the Roche Modular system((R)) Calcium method. The new method showed <10% interference with unconjugated or conjugated bilirubin (50 mg/dl), hemoglobin (1,000 mg/dl), lipids (1,000 mg/dl), and two magnetic resonance contrast agents containing Gadolinium (OptiMARK((R)) 1 mmol/l and Omniscan 1.5 mmol/l). On the contrary, the Roche Calcium method showed significant negative interference with gadolinium-containing contrast agents. We conclude that the ADVIA Ca_2 method can measure serum, plasma, or urine calcium concentrations accurately and is also free from interferences of gadolinium-containing agents.