European Metrology Institutes Research Articles

Metrology in health: challenges and solutions in infusion therapy and diagnostics.

The significance of Metrology in infusion therapy and diagnostics, both critical in health care safety and quality, is discussed in this article. Although infusion therapy is the most used form of drug administration, infusion errors are often made with reported dramatic effects in different applications, especially in neonatology. Adverse incidents, morbidity, and mortality have often been traced back to poor or inaccurate dosing. For critical infusion applications to vulnerable patients, well-controlled medication administration might be accomplished by improved dosing accuracy, traceable measurement of volume, flow, and pressure in existing drug delivery devices and in-line sensors operating at very low flow rates. To this end, the contribution of recently upgraded metrological infrastructures in European Metrology Institutes to a safer infusion therapy in health care is described in detail. Diagnostics, on the other hand isa sector characterized by rapid developments further triggered recently by the necessity for the management andprevention of infectious diseases like COVID-19. In this context, the impact of metrology in future large-scale commercialization of next generation diagnostics (e.g., point-of-care) is highlighted. Moreover, the latest contributions of Metrology in the development of traceable testing methods and protocols to ensure the sensitivity and accuracy of these devices are described.

The half-life of 129I

The radionuclide 129I is a long-lived fission product that decays to 129Xe by beta-particle emission. It is an important tracer in geological and biological processes and is considered one of the most important radionuclides to be assessed in studies of global circulation. It is also one of the major contributors to radiation dose from nuclear waste in a deep geological repository. Its half-life has been obtained by a combination of activity and mass concentration measurements in the frame of a cooperation of 6 European metrology institutes. The value obtained for the half-life of 129I is 16.14 (12) × 106 a, in good agreement with recommended data but with a significant improvement in the uncertainty.

Comparison of the Argon Triple-Point Temperature in Small Cells of Different Construction

The argon triple point (T_{90} = 83.8058,hbox {K}) is a fixed point of the International Temperature Scale of Preston-Thomas (Metrologia 27:3, 1990). Cells for realization of the fixed point have been manufactured by several European metrology institutes (Pavese in Metrologia 14:93, 1978; Pavese et al. in Temperature, part 1, American Institute of Physics, College Park, 2003; Hermier et al. in Temperature, part 1, American Institute of Physics, College Park, 2003; Pavese and Beciet in Modern gas-based temperature and pressure measurement, Springer, New York, 2013). The Institute of Low Temperature and Structure Research has in its disposal a few argon cells of various constructions used for calibration of capsule-type standard platinum resistance thermometers (CSPRT) that were produced within 40 years. These cells differ in terms of mechanical design and thermal properties, as well as source of gas filling the cell. This paper presents data on differences between temperature values obtained during the realization of the triple point of argon in these cells. For determination of the temperature, a heat-pulse method was applied (Pavese and Beciet in Modern gas-based temperature and pressure measurement, Springer, New York, 2013). The comparisons were performed using three CSPRTs. The temperatures difference was determined in relation to a reference function W(T)=R(T_{90})/R(271.16hbox {K}) in order to avoid an impact of CSPRT resistance drift between measurements in the argon cells. Melting curves and uncertainty budgets of the measurements are given in the paper. A construction of measuring apparatus is also presented in this paper.

European EMRP Projects About LED Lighting

Industrial and testing lighting laboratories underestimated the intrinsic metrological peculiarities of LED sources: concerns about performances, efficiency, ambiguous data and visual perception “de facto” slowed down their widespread implementation and their use in innovative systems in the first years of marketing. EU recognized these problems and funded projects with the European Metrology Research Programme (EMRP) to give a strong metrological basis to their optical, photometric and radiometric characterisation. The European Commission and the participating countries within the European Association of National Metrology Institutes (EURAMET) jointly support the EMRP. The overall goal of the EMRP is to accelerate innovation and competitiveness in Europe, enabling European metrology institutes, industrial organisations and academia to collaborate on joint research projects within specified fields. Among the EMRP programme two different 3 years projects about LED Lighting were funded in two different “Energy” calls: in 2010 “EMRP ENG05 Metrology for Solid State Lighting”, and in 2014 “EMRP ENG62 Metrology for Efficient and Safe Innovative Lighting”.

Comparison of asphere measurements by tactile and optical metrological instruments

A comparison of topography measurements of aspherical surfaces was carried out by European metrology institutes, other research institutes and a company as part of an European metrology research project. In this paper the results of this comparison are presented. Two artefacts were circulated, a small polymer coated aspherical lens with a clear aperture of about 12 mm, and a large conical convex lens with a clear aperture of 300 mm developed for the ESO Very Large Telescope. The participating laboratories were allowed to follow their own measurement strategies. Both tactile and optical measuring instruments were used, as well as single point and imaging techniques. The measured data were compared with respect to the root-mean-square (RMS), peak-to-valley and Zernike polynomial representations of the measured deviations from the nominal shape. The comparison shows for five out of eight measuring instruments/methods a very good agreement of the measured topographies within 14 nm (RMS).

Status and Strategy for Moisture Metrology in European Metrology Institutes

Measurement of moisture in materials presents many challenges, due to diverse measuring principles, sample interactions with atmosphere, and variation in what is measured (either water content alone or moisture including other liquids). Calibrations are variously referenced to published standard methods, primary calibration facilities, or certified reference materials, but each of these addresses limited substances and ranges of measurement. Overall, metrology infrastructure is not as fully developed or coherent for this field as it is for many other areas of measurement. In order to understand the metrology needs and to support developments, several European national metrology institutes (NMIs) have undertaken some collaborative activities. These have included a “cooperation in research” project for sharing of information, a survey of moisture capabilities at NMIs, the formulation of a strategy for moisture metrology at the NMI level, and a funded research project to develop improved metrology for the moisture field. This paper summarizes the information gathered, giving an overview of the status of moisture metrology at NMIs, and it reports a proposed strategy to improve the current situation.

Traceable size determination of nanoparticles, a comparison among European metrology institutes

Within the European iMERA-Plus project ‘Traceable Characterisation of Nanoparticles’ various particle measurement procedures were developed and finally a measurement comparison for particle size was carried out among seven laboratories across six national metrology institutes. Seven high quality particle samples made from three different materials and having nominal sizes in the range from 10 to 200 nm were used. The participants applied five fundamentally different measurement methods, atomic force microscopy, dynamic light scattering (DLS), small-angle x-ray scattering, scanning electron microscopy and scanning electron microscopy in transmission mode, and provided a total of 48 independent, traceable results. The comparison reference values were determined as weighted means based on the estimated measurement uncertainties of the participants. The comparison reference values have combined standard uncertainties smaller than 1.4 nm for particles with sizes up to 100 nm. All methods, except DLS, provided consistent results.

Consistency of practical salinity measurements traceable to primary conductivity standards: Euromet project 918

Measurements of practical salinity are based on conductivity measurements, which are traceable to the conductivity of a defined KCl reference solution. The conductivity of this reference solution must be traceable to the SI in order to state a reliable uncertainty for practical salinity measurements and to guarantee their comparability. Currently, the conductivity ratios from various old standard seawater batches are compared instead. However this method is inadequate on a long time-scale, which is important for oceanography studies, because it lacks a time-invariant reference. Therefore the equivalence of conductivity measurements traceable to primary conductivity standards has been investigated in Euromet project 918. Several European metrology institutes measured the conductivity of a 5 S/m KCl solution and the practical salinity of IAPSO standard seawater. The study estimates relative standard uncertainties to be of the order of 10−4 to 10−3 for such measurements.

Traceability in laboratory medicine

In laboratory medicine meaningful measurements are essential for diagnosis, risk assessment, treatment and monitoring of patients. Thus methods applied in diagnostic measurements must be accurate, precise, specific and comparable among laboratories. Inadequate or incorrect analytical performance has consequences for the patients, the clinicians, and the health care system. One key element of metrology is the traceability of a measurement result to the SI system ensuring comparable results. This principle is described in the ISO/TC 212/WG2 N65 prEN 17511 Standard. In addition to the principles of metrology, the clinical usefulness, the diagnostic needs, and the biological and disease associated variations in patients' specimens have to be considered when the analytical biases for diagnostic purposes are defined. It must be the general goal of diagnostic laboratories to produce results that are true and comparable worldwide. The recent European in vitro diagnostic (IVD) Directive 98/79 EC follows the above mentioned standard of the International Organization for Standardization (ISO) and the European Committee for Standardization (CEN) requesting its application for all IVD reagents used within the European Union. This new European legislation will have a worldwide impact on manufacturers and clinical laboratories and will be implemented in 2003. It states that "traceability of values assigned to calibrators and/or control materials must be assured through available reference measurement procedures and/or available reference materials of a higher order". Thus a worldwide reference system needs to be established by collaboration and mutual recognition between the United States National Institute of Standards and Technology (NIST), European Metrology Institutes (EUROMET), regulatory bodies (e.g. United States Food and Drug Administration, FDA) the IVD industry and professional organizations (e.g. International Federation of Clinical Chemistry and Laboratory Medicine, IFCC). In June 2002, in Paris, representatives of international and regional organizations and institutions decided to form the "Joint Committee on Traceability for Laboratory Medicine" (JCTLM), which will support industry in registration and licensing of the "CE" label to test systems conforming to the IVD Directive.