Traceable Reference Materials Research Articles

The design and implementation of regional creatine kinase/lactate dehydrogenase detection standardization

Objective To design and implement the standardization scheme of creatine kinase(CK)/lactate dehydrogenase(LDH) detection based on the present situation of clinical laboratory in Jiaxing, and attempt to reduce the imprecision and bias of the results in different clinical laboratories, obtain the traceable results. Methods According to the requirements of traceability in clinical laboratory, the CK/LDH standardization scheme was explored in Jiaxing from 2012, October to 2013, February,CK/LDH national reference material GBW09167, GBW09168 and serum pool were as samples for accuracy verification and impression in 33 local hospitals; then the reference materials GBW(E)03061 was as calibrator, while the GBWE03060 was performed as calibration verification material during the tests, the SOP for calibration made by the clinical quality control center was operated in calibration; as a result a scientific, practical standard scheme was developed. Results The equipment of clinical labrotories in Jiaxing are all imported, the laboratory management is well.However the bias of CK is -7%-12% and the bias of LDH is above -22%-15%. And then the standardization scheme was implemented in 6 Laboratories in which CV was less than 2%, and high-quality data of 5 laboratories are as follows:imprecision of CK and LDH in different labs were reduced from 4.95%-6.55% to 1.81%-2.33% and 5.75%-11.68% to 1.39%-1.80% individually， bias for CK is reduced from -0.84 %-6.23% to -0.15%-2.44% ; while in lactate dehydrogenase test, the bias is decreased from -10.18%-0.34% to -3.07%-0.58% . Conclusion Using the commutable and traceable reference material as calibrator, strengening the laboratory management such as making a calibration SOP will be a effective methods to realize the standardization in measurement.（Chin J Lab Med，2014,37：947-950） Key words: Creatine kinase; Lactate dehydrogenases; Reference standards; Laboratories, hospital; Research design

Quality control issues related to assessment of body composition.

There are no internationally agreed quality standards for the measurement of stature, weight, and body composition. This lack of agreement constrains the quality of work in nutrition and must be addressed in order to build systemic capacity within the Scaling Up Nutrition agenda. There is a need to reach agreement and define standards of performance and the required training to be able to demonstrate the competency of those responsible for making the measurements. This, together with the adoption of standardized protocols, traceable reference materials, quality assurance frameworks, and publication guidance, would mark an important first step in improving the conduct and interpretation of measurements of growth and body composition.

Development and Verification of Air Balance Gas Primary Standards for the Measurement of Nitrous Oxide at Atmospheric Levels

The Gas Metrology Group at the National Institute of Standards and Technology (NIST) became active in developing primary standards at ambient levels of N2O in the 1980s, and this has continued through to the present. In recent years, interest in NIST-traceable standards has increased-not only at the ambient level of approximately 325 nmol mol(-1) (ppb) but at micromole per mole (ppm) levels as well. In order to support two in-process dry whole air standard reference materials (SRMs 1720 and 1721) and the NIST Traceable Reference Materials (NTRM) program, a project was implemented in the Gas Metrology Group to produce a complete suite of new primary standard materials (PSMs) of N2O with synthetic air (O2/N2) as the balance gas. Six levels of dilution, approximately 1 order of magnitude apart, were gravimetrically prepared and verified. Each level serves as the "parent mix" for the next level. This discussion describes the process of producing each level and then verifying its amount-of-substance fraction. Expanded uncertainties, k = 2, of 0.025% relative to the gravimetric amount-of-substance fraction were obtained at the ambient level. One standard from the final group of standards at the ambient amount-of-substance fraction level was compared with standards from the National Oceanographic and Atmospheric Administration and the Scripps Institution of Oceanography, two organizations experienced in gas standards preparation and ambient whole air measurements, and shows agreement to 0.07 nmol mol(-1) (0.02% relative) and 0.20 nmol mol(-1) (0.06% relative), respectively.

Traceable measurement of specific organic species at industrially relevant surface by infrared spectroscopy

Deposition of organic materials on hardware, high tech vacuum components and spacecraft materials is a common risk in the fabrication of space industry instrumentations, which often leads to impair their functionality. Metrological procedures that meet the industrial needs are urgently required in order to detect and quantify a contamination at relevant surfaces. In this work, a direct method based on Fourier transform infrared spectroscopy (FTIR) was developed providing both qualitative and quantitative information on the source of the contamination. According to Thales Alenia Space (TAS) requirements, three main categories of contaminants were selected: hydrocarbons, esters and silicones. Traceable reference materials belonged to these categories were chosen and used for calibration equipment. A practice to assist in the preparation of the calibration curves of the selected standards within the concentration range useful for practical applications is here presented. This methodology was further applied in the framework of BepiColombo program to detect organic contamination into TAS2 and 2B cleanrooms, and it resulted to meet the industrial needs for monitoring surface contaminants. Copyright © 2014 John Wiley & Sons, Ltd.

Development of Prompt Prodcutopn of SI Traceable Reference Materials for Analysis of Pesticides in Food Residue

Development of Prompt Prodcutopn of SI Traceable Reference Materials for Analysis of Pesticides in Food Residue

A Commutable Cytomegalovirus Calibrator Is Required to Improve the Agreement of Viral Load Values between Laboratories

Viral load testing for cytomegalovirus (CMV) is an important diagnostic tool for the management of transplant recipients and immunocompromised individuals; however, inconsistency among laboratories in quantitative measurements of viral load limits interinstitutional comparisons. These inconsistencies stem from the lack of assays cleared by the US Food and Drug Administration, the absence of international standards, the wide variety of CMV-extraction and -detection methods, and differences in materials used for calibration. A critical component of standardization is the use of calibrators that are traceable and commutable. Bland-Altman plots and prediction ellipses were used to test the commutability of 2 CMV calibrators for 2 different quantification methods. Tests with 2 methods showed 1 calibrator to be commutable and the other to be noncommutable. The results for the commutable calibrator were within the 95% prediction interval of the clinical samples in the Bland-Altman plot and within the 95% prediction ellipse for a simulated commutable calibrator, whereas the results for the noncommutable calibrator were not within these prediction intervals. When used to calibrate patient results, only the commutable calibrator, the OptiQuant CMV(tc) Calibration Panel, significantly improved the comparability of viral loads for the 2 different measurement methods. This study demonstrates that an important goal in the effort to improve healthcare for patients with CMV-related disease is the establishment of traceable and commutable reference materials, including both calibrators and controls. .

Calibration of a white light interferometer for the measurement of micro-scale dimensions

Calibration is central to most measurement procedures. This is especially true in those cases where a large number of difficult-to-identify and difficult-to-control factors hinder the experimenters in their efforts to obtain reliable measurement results. Dimensional measurements of features on the micro- and nano-scales is one such case. A white-light interferometer (WLI) microscope can perform measurements of a variety of measurands over a broad dimensional range: from surface texture characterisations on the nano-scale to measurements of step heights of several millimetres. Calibration methods based on the hypothesis of a linear calibration curve can be inadequate to express the relationship between measurement results and traceable reference materials (RMs). A calibration procedure built into a commercially available WLI microscope is critically compared with methods presented in an international standard. This comparison is enabled by a cost-effective procedure for establishing traceable RMs in the micro-range. Advantages of calibration procedures based on more than one RM are then demonstrated within the ranges from 180.5 to 219.5 μm and from 1.5 to 501.5 μm. Calibration methods involving regression modelling of transformed measurement results are considered for these two intervals to overcome the highlighted weaknesses of the calibration procedure built in the examined WLI.

Differences between propane in nitrogen versus air matrix analyzed using gas chromatography with flame-ionization detection

New US Federal low-level automobile emission requirements, such as Zero Level Emission Vehicle (ZLEV), for hydrocarbons and other species have resulted in manufacturers need for new certified reference materials. The new emission requirement for hydrocarbons requires the use, by automobile manufacturing testing facilities, of 100 nmol/mol (ppb) propane in air gas standard. Emission measurement instruments are required, by Federal law, to be calibrated with the US National Institute of Standards and Technology (NIST) traceable reference materials. A NIST Standard Reference Material (SRM) containing 100 nmol/mol propane has been developed. During the development of this SRM a critical question arose as to the matrix of the primary propane standards. The automobile companies make their measurements using total hydrocarbon analyzers with flame-ionization detectors which integrate all hydrocarbons in a sample. NIST uses gas chromatography/flame-ionization detection (GC/FID) with a column to separate all components. Since the SRM mixtures were in air, the question as to the effect of oxygen on the detector arose. To investigate this effect, two suites of propane primary standards were developed: one in air and the other in nitrogen. The two suites of primary standards were analyzed using NIST methods, and the concentration of propane in an air mixture was determined. The results show that there was a difference of 0.63% in the propane concentration determined versus air and nitrogen suites.

General concepts for traceability in environmental radioactivity monitoring

Measurement traceability is an important component for the realization of the becquerel. For radioanalytical measurements, the definition of measurement traceability must include sub-sample processing operations prior to instrument measurement. The most effective demonstration that measurement traceability and the SI becquerel have been realized isparticipation in suitable proficiency testing using appropriate traceable reference materials,an embedded system of analytical quality control andaudit regimes covering all aspects of laboratory operation.Guidance documents are available for a number of measurement fields such as environmental and bioassay measurement that recognize the important utility of measurement tractability as part of the supporting metrology infrastructure. Non-radiometric methods, mainly mass spectrometry based, as well as field (or in situ) measurements are also available for the assay of radioactive species. These are not explicitly treated in this paper but should be consistent with the approaches described here.

Development of a 100 nmol mol−1 propane-in-air SRM for automobile-exhaust testing for new low-emission requirements

New US federal low-level automobile emission requirements, for example zero-level-emission vehicle (ZLEV), for hydrocarbons and other species, have resulted in the need by manufacturers for new certified reference materials. The new emission requirement for hydrocarbons requires the use, by automobile manufacturing testing facilities, of a 100 nmol mol(-1) propane in air gas standard. Emission-measurement instruments are required, by federal law, to be calibrated with National Institute of Standards and Technology (NIST) traceable reference materials. Because a NIST standard reference material (SRM) containing 100 nmol mol(-1) propane was not available, the US Environmental Protection Agency (EPA) and the Automobile Industry/Government Emissions Research Consortium (AIGER) requested that NIST develop such an SRM. A cylinder lot of 30 gas mixtures containing 100 nmol mol(-1) propane in air was prepared in 6-L aluminium gas cylinders by a specialty gas company and delivered to the Gas Metrology Group at NIST. Another mixture, contained in a 30-L aluminium cylinder and included in the lot, was used as a lot standard (LS). Using gas chromatography with flame-ionization detection all 30 samples were compared to the LS to obtain the average of six peak-area ratios to the LS for each sample with standard deviations of <0.31%. The average sample-to-LS ratio determinations resulted in a range of 0.9828 to 0.9888, a spread of 0.0060, which corresponds to a relative standard deviation of 0.15% of the average for all 30 samples. NIST developed its first set of five propane in air primary gravimetric standards covering a concentration range 91 to 103 nmol mol(-1) with relative uncertainties of 0.15%. This new suite of propane gravimetric standards was used to analyze and assign a concentration value to the SRM LS. On the basis of these data each SRM sample was individually certified, furnishing the desired relative expanded uncertainty of +/-0.5%. Because automobile companies use total hydrocarbons to make their measurements, it was also vital to assign a methane concentration to the SRM samples. Some of the SRM samples were analyzed and found to contain 1.2 nmol mol(-1) methane. Twenty-five of the samples were certified and released as SRM 2765.

Analytical validation of quality control materials for Huntington’s disease examination

The expansion of molecular diagnostics using nucleic acid technologies in clinical and public health practice has increased the need for appropriate reference materials and verified quality-control materials for quality assurance, test validation, proficiency testing and the development of new examination procedures. Good laboratory practice requires the use of reference materials to establish an examination procedure and assess the variability of the results. Reference materials are also required to assess the assay on a daily basis and to normalize results collected among different laboratories. Despite the growing volume, the rapidly increasing number of tests being offered, and the necessary routine use, certified reference materials are often not available. There is a wide range of human genetic bio-assays for which there are no available traceable certified reference materials. Several initiatives have been organized to provide well-characterized quality control specimens (e.g., cell lines) with known DNA mutations for use in diagnostics. Mutations are confirmed with bi-directional DNA sequence analysis, which is considered the reference examination procedure. In the field of personalized medicine, NIST has created and validated Standard Reference Material® 2399 for fragile X examinations. Herein we describe our characterization of candidate reference materials for Huntington’s disease genetic examination. Bi-directional DNA sequencing confirmed the size of the CAG repeat contained on each allele from patient derived materials. Amplification and capillary electrophoresis of the CAG repeats had an uncertainty ranging from 2.06%CV to 7.83%CV.

On practical metrology and chemical analysis: legal, institutional and technical evolutions in the Australian national measurement system

Economic and technological change, regional and international trade and the globalisation of industry have led to intense pressures for improvements to analytical quality, reliability and comparability. Of central importance are national traceability structures connecting chemical measurements in the field with internationally accepted measurement units and their practical realisations. Australia has a developed physical and engineering measurement system, a legislative framework for analytical traceability and, in the National Association of Testing Authorities, a recognised laboratory accreditation system. The need has been identified to develop the technical capability to perform matrix-independent reference measurements for the certification of traceable reference materials, useable as practical analytical etalons to establish metrological control systems in field measurements for amounts of substance. Recently, a unique collaborative consortium has proposed a National Analytical Reference Laboratory (NARL). The NARL is designed to be a metrological mass spectrometry facility for the transference of measurement units to more widely useable chemical measurement standards and reference materials.

Standardisation in the industrial R&amp;D laboratory

Within industrial thermal analysis applications there is an increasing requirement for more rigorous standardisation to ensure that the data obtained can be reproduced within any other laboratory, using the same procedures. Fundamental to all Quality Accreditation programmes is the need to generate ‘equivalent data’. The paper highlights TA applications where this is not achieved despite the use of standard calibration procedures, where true calibration is difficult to establish due to hardware/software design limitations or the absence of proven and traceable reference materials. Lack of standardisation can have important commercial or legal consequences for both instrument manufacturer and end-user.