Nordic Laboratories Research Articles

Analyzing alpha emitting isotopes of Pu, Am and Cm from NPP water samples: an intercomparison of Nordic radiochemical laboratories

Radioanalytical methods for the determination of isotopes of Pu, Am and Cm in water samples from nuclear power plants were compared and further developed in a Nordic project (Optimethod) through two intercomparison exercises among Nordic laboratories. With this intercomparison, the analytical performance of some laboratories was improved by modification of the analytical method and adopting new techniques. The obtained results from the two intercomparisons for alpha emitting transuranium isotopes are presented, and the lessons learnt from these intercomparison exercises are discussed.

Høj Stene – en monumental skibssætning ved Gudenåen

Høj Stene – en monumental skibssætning ved Gudenåen

Handling of hemolyzed serum samples in clinical chemistry laboratories: the Nordic hemolysis project.

Background Some clinical chemistry measurement methods are vulnerable to interference if hemolyzed serum samples are used. The aims of this study were: (1) to obtain updated information about how hemolysis affects clinical chemistry test results on different instrument platforms used in Nordic laboratories, and (2) to obtain data on how test results from hemolyzed samples are reported in Nordic laboratories. Methods Four identical samples containing different degrees of hemolysis were prepared and distributed to 145 laboratories in the Nordic countries. The laboratories were asked to measure the concentration of cell-free hemoglobin (Hb), together with 15 clinical chemistry analytes. In addition, the laboratories completed a questionnaire about how hemolyzed samples are handled and reported. Results Automated detection of hemolysis in all routine patient samples was used by 63% of laboratories, and 88% had written procedures on how to handle hemolyzed samples. The different instrument platforms measured comparable mean Hb concentrations in the four samples. For most analytes, hemolysis caused a homogenous degree of interference regardless of the instrument platform used, except for alkaline phosphatase (ALP), bilirubin (total) and creatine kinase (CK). The recommended cut-off points for rejection of a result varied substantially between the manufacturers. The laboratories differed in how they reported test results, even when they used the same type of instrument. Conclusions Most of the analytes were homogeneously affected by hemolysis, regardless of the instrument used. There is large variation, however, between the laboratories on how they report test results from hemolyzed samples, even when they use the same type of instrument.

Performance of the EUCAST disc diffusion method and two MIC methods in detection of Enterobacteriaceae with reduced susceptibility to meropenem: the NordicAST CPE study.

Objectives To examine performance of EUCAST disc diffusion and supplementary MIC methods for detection of Enterobacteriaceae with reduced susceptibility to meropenem using EUCAST screening recommendations. Methods Sixty-one Nordic laboratories delivered data on EUCAST disc diffusion (n = 61), semi-automated meropenem MIC (n = 23; VITEK2, n = 20 and Phoenix, n = 3) and gradient meropenem MIC (n = 58) methods. The strains (n = 27) included the major carbapenemase classes (A, n = 4; B, n = 9; D, n = 6) involved in the global spread of carbapenemase-producing Enterobacteriaceae (CPE) and non-CPE strains (n = 8) covering a range of broth microdilution (BMD) meropenem MICs. Results A triplicate Klebsiella variicola (meropenem MIC 0.5 mg/L) harbouring OXA-48 and Escherichia coli ATCC 25922 showed an overall good precision. Meropenem zone diameters below the EUCAST screening cut-off (<27 mm) were reported for strains with MIC ≥1 mg/L (n = 21), irrespective of resistance mechanism. For three strains (MIC = 0.5 mg/L) with OXA-48/-181, eight laboratories provided meropenem zone diameters above the screening cut-off. Very major errors (VMEs) were not observed. The overall distributions of major errors (MEs) and minor errors (mEs) were 9% and 36% (disc diffusion), 26% and 18% (VITEK2) and 7% and 20% (gradient MIC), respectively. Differences in ME and mE distributions between disc diffusion and MIC gradient tests compared with semi-automated methods were significant (P < 0.0001), using BMD MICs as a reference for categorization. Conclusions The EUCAST disc diffusion method is a robust method to screen for CPE but isolates with meropenem MICs <1 mg/L pose challenges. The high ME rate in semi-automated methods might deter appropriate use of carbapenems in CPE infections with limited therapeutic options.

Performance of the EUCAST disc diffusion method and two MIC methods in detection of Enterobacteriaceae with reduced susceptibility to meropenem: the NordicAST CPE study.

ObjectivesTo examine performance of EUCAST disc diffusion and supplementary MIC methods for detection of Enterobacteriaceae with reduced susceptibility to meropenem using EUCAST screening recommendations.MethodsSixty-one Nordic laboratories delivered data on EUCAST disc diffusion (n = 61), semi-automated meropenem MIC (n = 23; VITEK2, n = 20 and Phoenix, n = 3) and gradient meropenem MIC (n = 58) methods. The strains (n = 27) included the major carbapenemase classes (A, n = 4; B, n = 9; D, n = 6) involved in the global spread of carbapenemase-producing Enterobacteriaceae (CPE) and non-CPE strains (n = 8) covering a range of broth microdilution (BMD) meropenem MICs.ResultsA triplicate Klebsiella variicola (meropenem MIC 0.5 mg/L) harbouring OXA-48 and Escherichia coli ATCC 25922 showed an overall good precision. Meropenem zone diameters below the EUCAST screening cut-off (<27 mm) were reported for strains with MIC ≥1 mg/L (n = 21), irrespective of resistance mechanism. For three strains (MIC = 0.5 mg/L) with OXA-48/-181, eight laboratories provided meropenem zone diameters above the screening cut-off. Very major errors (VMEs) were not observed. The overall distributions of major errors (MEs) and minor errors (mEs) were 9% and 36% (disc diffusion), 26% and 18% (VITEK2) and 7% and 20% (gradient MIC), respectively. Differences in ME and mE distributions between disc diffusion and MIC gradient tests compared with semi-automated methods were significant (P < 0.0001), using BMD MICs as a reference for categorization.ConclusionsThe EUCAST disc diffusion method is a robust method to screen for CPE but isolates with meropenem MICs <1 mg/L pose challenges. The high ME rate in semi-automated methods might deter appropriate use of carbapenems in CPE infections with limited therapeutic options.

Reference intervals for the P-Albumin bromocresol purple method

Correct reference intervals are an important part of test results. As establishing own reference intervals is a very expensive task, the NORIP reference intervals are often transferred for use in Nordic laboratories. The NORIP reference interval on P-Albumin was here compared to current results for laboratories using the bromocresol purple (BCP) method for P-Albumin. External quality control reports were used to investigate the change in levels between the BCP and BCG methods on P-Albumin. An algorithm was built for extracting and isolating the laboratory’s healthy subject population. The algorithm was used to extract test results from the laboratory information system. Parametric and non-parametric statistical methods were used to evaluate the P-Albumin test result populations. The indirect method used here clearly shows that the NORIP reference intervals for P-Albumin are not fit for the current bromocresol purple methods. The method was also used to suggest new reference interval limits.

Conclusion. Globalization and language in the Nordic countries: conditions and consequences

1. Comparing empirical findings with the “mountain peak model”In the introduction to this volume, we presented a “mountain peak model” of Nordic purism based on evidence showing that language scholars and lay people are very much in agreement as to where we find the more purist languages and communities in the Nordic area.The peak of openness to foreign influence is to be found in “the middle”, i.e. in Denmark and Sweden, with gradually diminishing openness as we move towards the periphery, be it either westwards across Norway and The Faroes to Iceland or eastwards across Swedish-speaking Finland to Finnish-speaking Finland. In this conclusion to the volume, we will sum-marize the empirical findings presented in the volume, findings for use and attitudes alike, and compare them with the mountain peak model. That way, we may be able to estimate the nature of the cross-national ideologi-cal uniformity on which the model is based. Is the commonly shared repre-sentation of purism differences nothing but an ideological fact, or is there a reality to the mountain peak picture?Furthermore, we will follow up on the introduction’s presentation of the “Nordic laboratory” as a well-chosen place to study the relative impor-tance in language change of language-internal structural factors on the one hand and language-external socio-historical factors on the other hand. However, a complicating fact of our laboratory setting needs to be men-tioned before we proceed. It is a fact that the centre vs. periphery distinc-tion of the mountain peak model does not only correspond to a similarity vs. difference distinction in terms of the linguistic relationships to English, but also to a dominance vs. subordination distinction in terms of the histo-rical relationships between the Nordic communities. In other words, if we find linguistic purism to be more characteristic of the peripheral communi-ties than of the central ones we may be hard put to it to tell whether this is caused by linguistic or socio-historical realities.

Introduction. The linguistic consequences of globalization: the Nordic laboratory

As is well-known from the literature on language contact (e.g. Weinreich 1953; Thomason and Kaufman 1988) the factors and forces that are in play in close and longstanding contact between (speakers of ) two languages are both linguistic and social in nature, and involve both quantitative and qualitative relationships. Indeed, the outcome of language contact is a question of numbers and frequencies in terms of use and users, of sameness vs. difference in terms of linguistic structure, of dominance vs. subordination in terms of socio-historical contexts, etc. The history of the Nordic communities is rich in illustrative examples of such relationships, with Denmark and Sweden as the stronger communities, opposing each other “in the middle” of the Nordic area, all while dominating “the periphery” — westwards in the case of Denmark and Danish with a long history in Norway, the Faroes, Iceland and Greenland — eastwards in the case of Sweden and Swedish with a long history in Finland. And we may add the linguistic and socio-historical complexities that relate the Sami people in the far north to the southern majority populations of Norway, Sweden and Finland. Superposed on these intra-Nordic relationships, so to speak, “foreign” cultures and languages — most importantly Latin, German and French — have reached the Nordic area as a whole throughout its history, leaving a similar imprint, with variations, on its languages. The complex linguistic and socio-historical relationships hinted at here are among the most thoroughly studied and documented in the world (Bandle et al. 2002–2005). Against this background, it seems to us that the Nordic area makes up a well-suited “laboratory” for research into the contexts and consequences of today’s globalization and the general advance of English. This is a main consideration behind a large contrastive project which has been running since 2001 in seven Nordic communities, including (from west to east): Iceland, The Faroe Islands, Norway, Denmark, Sweden, Swedish-speaking Finland, and Finnish-speaking Finland. (The Greenlandic and Sami AUTHOR’S COPY | AUTORENEXEMPLAR

Intercomparison of Rn-222 determination from groundwater

An intercomparison exercise on Rn-222 determination in groundwater was organized between eight Nordic laboratories. The individual laboratory results were in most cases within 20% of the median value and within reported uncertainties. Considering the particular difficulties in preparing, transporting and analyzing Rn-222, being a gaseous radionuclide, the results indicate a high analytical capability among the Nordic laboratories. In order to maintain a high analytical quality, similar intercomparisons will also be needed in the future.

Validation of NMKL method No. 136 — Listeria monocytogenes, detection and enumeration in foods and feed

A collaborative study was organised to define the performance characteristics of the revised NMKL Method No.136 “ Listeria monocytogenes. Detection and enumeration in foods”. Chromogenic L. monocytogenes specific plating medium, Agar Listeria according to Ottaviani and Agosti (ALOA) was introduced in the revised method in order to improve the sensitivity and specificity of the method, and to shorten the analysis time. Efficacy of ALOA One Day from AES (ready-to-use agar in bottles), Listeria Chromogenic Agar (Agosti and Ottaviani Listeria agar) from Lab M (LCA) (dehydrated powder), Chromogenic Listeria Agar Plates from Oxoid (OCLA) (ready-to-use plates) and L. monocytogenes blood agar medium LMBA from Lab M (dehydrated powder) were tested . Three types of food matrices (vacuum-packed hot-smoked salmon, soft cheese and cooked ham) and one feed matrix (wheat grain) inoculated with two levels of L. monocytogenes with or without L. innocua were used in the study. A total of 24 samples were analysed both in the detection and enumeration part of the study by 18 and 17 Nordic laboratories, respectively. The sensitivities of ALOA, LCA, OCLA and LMBA in the detection of L. monocytogenes in food samples after one-step enrichment (Half-Fraser) were 94.4–96.4% and after two-step enrichment (Half-Fraser followed by Fraser) 97.7–100%. For wheat grain the respective figures were 84.7–88.9% and 90.3–93.1%, respectively. The precision characteristics were generally good for the enumeration of L. monocytogenes in the food samples with high levels of inoculation. Several poor values obtained from the food samples with low levels of inoculation probably reflect high uncertainty of measurement when less than 10 cfu/g was counted. Poor values obtained from the wheat grain samples by any of the media evaluated were due to poor precision for feed samples. According to the study, the revised NMKL Method No.136, 4th ed. showed excellent results in the detection and satisfactory results in the enumeration of L. monocytogenes in foods. The results for the detection of L.monocytogenes in wheat grain were good, but the method cannot be recommended for the enumeration of L. monocytogenes in feed-stuffs. Any one of the media evaluated can interchangeably be used as an obligatory isolation medium for the detection and enumeration of L. monocytogenes in foods, and for the detection in feed-stuffs. The L. monocytogenes specific plating media that were evaluated shorten the time of analysis and significantly reduce the work load. The detection of positive samples mostly after Half-Fraser enrichment, reduces the analysis time further, and makes it possible to skip the secondary enrichment. However, secondary enrichment cannot be totally left out, because samples with low levels of L. monocytogenes, with high levels of competing flora, and with injured L. monocytogenes, do need secondary enrichment.

Nordic CML Study Group Quality and Standardization Rounds for Quantitative RT-PCR of BCR-ABL To Facilitate Reporting on the International Scale.

Measuring the level of BCR-ABL transcripts by real-time quantitative polymerase chain reaction (RQ-PCR) has been shown to be a highly sensitive and specific method for evaluating residual disease burden in chronic myeloid leukemia (CML). In the IRIS trial, a 3-log reduction of BCR-ABL transcripts from a baseline median pre-treatment level was termed a “major molecular response”, and achieving this degree of minimal residual disease (MRD) was related to a more favorable prognosis. Recently it was proposed that the residual disease scale used in the IRIS trial should be named “International Scale” (IS) and this scale is recommended to be used in future studies of CML treatment. Since the baseline in the IRIS trial can no longer be reproduced, a project for distributing reference material has been initiated by the original IRIS study reference laboratory in Adelaide and by a secondary European reference laboratory in Mannheim. Within the framework of the Nordic CML Study Group, RQ-PCR for BCR-ABL is routinely performed in 13 clinical laboratories located in Finland, Sweden, Norway and Denmark. Only two Nordic laboratories had an opportunity to receive reference material from Mannheim. Therefore it was necessary to complement this effort by performing a Nordic quality and standardization round based not only on the external reference material but also on local pre-treatment samples from CML patients. Thus each of the participating laboratories prepared samples representing minimal residual disease and also additional pre-treatment CML samples. These samples were divided into 13 identical aliquots and distributed to all other participants this summer. By this approach we can not only check reproducibility of measurements, but also evaluate different laboratory specific steps in the procedures, such as the importance of source cell material, RNA isolation method, control genes, model of thermocycler and methods/enzymes used in reverse-transcription and RQ-PCR. Based on the results, provisional conversion factors for adjustment of the BCR-ABL transcript levels to the International Scale will be produced for all participating laboratories. This work is an example on successful international RQ-PCR standardization, which is essential for clinical and research estimation of MRD in CML patients.

Diagnostics of fungal infections in the Nordic countries: We still need to improve!

A Nordic External Quality Assessment programme in medical mycology was established in 2005. In order to monitor not 'best practice' but the level of routine diagnostics, specimens were designed to resemble clinical samples and laboratories were asked to handle the samples like routine samples. Five simulated clinical samples were distributed to 59 participating Nordic laboratories of clinical microbiology. The specimens contained the following microorganisms: 1) Candida glabrata and C. albicans in a ratio of 1:20; 2) Cryptococcus neoformans; 3) Aspergillus fumigatus, C. albicans and Enterobacter cloacae; 4) C. tropicalis, Klebsiella pneumonia and Enterococcus faecium; 5) None. 66% of the laboratories failed to detect the C. glabrata isolate in sample no. 1. 34% of the laboratories reporting susceptibility results incorrectly reported the Cryptococcus neoformans isolate as fluconazole susceptible. 24% of the laboratories failed to detect Aspergillus fumigatus in specimen no. 3 despite the accompanying clinical information notifying that it was a BAL sample from a neutropenic patient in an ICU. In conclusion, this distribution of simulated clinical samples illustrates that the traditional quality assessment programmes may give a false sense of satisfactory performance, that mycological diagnosis is difficult, and that there is a need of further improvement and attention.

Accurate calibration of a laboratory beta particle dose rate for dating purposes

This paper describes a novel method for calibration of the dose rate provided by a beta source used for luminescence dating. The calibration has been performed using an in-house calibration quartz that is given a dose in a Co-60 gamma ray facility. The gamma dose to the calibration quartz was calculated using Fricke dosimetry on simultaneously irradiated Fricke solution and Monte-Carlo simulations. An overall uncertainty in the dose to quartz of 0.6% (1 sigma) was achieved. The single aliquot regenerative dose (SAR) procedure was used to determine the irradiation time of the beta source needed to deliver the same dose to the sample. Results for a range of doses were combined by plotting irradiation time versus dose. A fit through the data points yielded the dose rate provided by the beta source at the sample position. This procedure resulted in an overall uncertainty in the beta dose rate of 0.9% (1 sigma). The beta dose rate was found to be in perfect agreement with an independent calibration using irradiated quartz provided by the Nordic Laboratory for Luminescence dating.

Inter-laboratory comparison of a fatigue test

Abstract This paper describes a fatigue testing inter-laboratory comparison between six Nordic laboratories, which performed fatigue tests on steel specimens. The specimens were tested with three different stress levels (maximum stress) and with a load ratio R = Smin/Smax = 0.1. Each laboratory tested four specimens at each stress level. The participating laboratories reported the results together with the uncertainty of measurement. The calculated results showed a significant difference between laboratories. However, when the differences in modelling were taken into consideration, no significant differences between the laboratories remained. Significant problems connected with calculations of uncertainty of measurement were detected. One of the major conclusions from the study is that it is of great importance how fatigue tests are reported, e.g. the method of modelling. Better knowledge of how to report fatigue tests, including uncertainty of measurement, as well as a more generally accepted way of reporting such tests – and especially how to treat run-outs – would be a great improvement for the customers of the laboratories.

Reflections regarding uncertainty of measurement, on the results of a Nordic fatigue test interlaboratory comparison

This paper presents the experiences of calculation and reporting uncertainty of measurement in fatigue testing. Six Nordic laboratories performed fatigue tests on steel specimens. The laboratories also reported their results concerning uncertainty of measurement and how they calculated it. The results show large differences in the way the uncertainties of measurement were calculated and reported. No laboratory included the most significant uncertainty source, bending stress (due to misalignment of the testing machine, “incorrect” specimens and/or incorrectly mounted specimens), when calculating the uncertainty of measurement. Several laboratories did not calculate the uncertainty of measurement in accordance with the Guide to the Expression of Uncertainty in Measurement (GUM) [1].

Nordic Reference Interval Project Bio‐bank and Database (NOBIDA): a source for future estimation and retrospective evaluation of reference intervals

In the Nordic Reference Interval Project 2000 (NORIP) serum, Li‐heparin plasma and EDTA buffy coat were collected at 102 laboratories in 5 Nordic countries from healthy individuals aged 18 years or more and evenly distributed for laboratory, gender and age. Multiple aliquots of these samples from each of about 3000 persons are now stored at the Nordic Reference Interval Project Bio‐bank and Database (NOBIDA) at a temperature of below −80°C. The commutable NFKK Reference Serum X with certified values traceable to reference methods and measured in NORIP in the same series as the samples is also available from NOBIDA. Data describing the person and the sample conditions are stored together with analytical results and data describing the measurement systems. The bio‐bank along with material and data is administered by the NOBIDA committee on behalf of the NFKK (Scandinavian Society of Clinical Chemistry) to be used by Nordic laboratories for any purpose beneficial to the development of clinical biochemistry in general and particularly for creating reference intervals for other biochemical properties than those established by NORIP. Furthermore, research on the already stored information alone is encouraged. Thus colleagues are now welcome to use this extensive material for research and development in clinical biochemistry.

The Nordic Trueness Project 2002: use of reference measurement procedure values in a general clinical chemistry survey

Up to 136 laboratories participated in a joint effort to assess the trueness of routine measurements for 14 serum components. An unmodified, fresh‐frozen human serum (“IMEP‐17 Material 1”), produced for an international inter‐laboratory comparison, served as the “master material”. The serum had assigned values of the highest available metrological quality, and is assumed to involve no or negligible commutability problems. The material was used in the assignment of traceable values to two other reference sera, “CAL” and “X”, through parallel measurements on the three materials according to a common protocol. In this transfer process, uncertainty estimates were provided for all values. The material CAL had been supplied with reference measurement procedure values in 1997, and the two sets of assigned values agreed well. A lyophilized control serum “HK02” was also included in the routine analysis series. It, too, had assigned values based on reference measurement procedures. Significant matrix effects were found. The project has provided:Assigned traceable values for 14 components in a fresh‐frozen serum, available to Nordic laboratories for the coming years as “NFKK reference serum X”.Confirmation of earlier assigned reference measurement procedure values for a number of components in CAL, the main calibrator in the Nordic Reference Interval Project (NORIP). The transferred values will now serve as the primary reference.Evidence of long‐term stability (≥5 years) of the fresh‐frozen serum CAL when stored at −80°C.Evidence of substantial matrix effects in the processed serum HK02. The findings should be used to discuss to what extent reference measurement procedure values are useful and cost‐efficient for this type of material.

Prevalence of resistance to ampicillin, gentamicin and vancomycin in Enterococcus faecalis and Enterococcus faecium isolates from clinical specimens and use of antimicrobials in five Nordic hospitals.

We determined the species distribution and prevalence of ampicillin resistance, high-level gentamicin resistance (HLGR) and vancomycin resistance among clinical enterococcal isolates from five Nordic laboratories (Bergen, Tromsø, Uppsala, Aarhus and Reykjavik). Isolates represented three different groups: (i) all blood culture isolates from 1999; (ii) consecutive in-patient isolates (maximum 40); and (iii) consecutive outpatient isolates (maximum 40) collected during March to May 2000. Antimicrobial use data were collected at the national and hospital level. A high proportion (31.4%) of Enterococcus faecium was detected among blood culture isolates, in contrast to only 4.2% among isolates from outpatients. Ampicillin resistance was not found in Enterococcus faecalis, in contrast to 48.8% in E. faecium isolates. HLGR rates varied considerably between laboratories (1.1-27.6%). Acquired vancomycin resistance was not detected. There were no significant differences in the prevalences of HLGR between in-patient and outpatient isolates at individual hospitals. A cluster of clonally related ampicillin-resistant and HLGR E. faecium isolates was demonstrated in one of the hospitals. The lowest level of hospital antimicrobial use, the lowest proportion of E. faecium and the lowest prevalence of resistance were observed in Reykjavik. The study showed a relatively low level of resistance in enterococci, as compared with most European countries and the USA. However, there were large differences between hospitals with regard to the relative proportion of E. faecium isolates, their susceptibility to ampicillin and gentamicin, as well as the prevalence of HLGR in E. faecalis isolates. This indicates a potential for further improvement of antibiotic policies, and possibly hospital infection control, to maintain the low resistance levels observed in these countries.

Nordic laboratory intercomparison of supercritical fluid extraction for the determination of total petroleum hydrocarbon, polychlorinated biphenyls and polycyclic aromatic hydrocarbons in soil

Two developed supercritical fluid extraction (SFE) methods [one for the determination of total petroleum hydrocarbon (TPH) and polychlorinated biphenyls (PCBs), and one for polycyclic aromatic hydrocarbons (PAHs) and creosote components in soil] were evaluated in a Nordic laboratory intercomparison study with 11 participating laboratories. The interlaboratory comparison showed that excellent recoveries can be obtained with SFE for PAHs and PCBs compared to the solvent extraction. For the TPH, the recoveries were significantly higher than those achieved with solvent extraction. The accuracy, expressed as the relative standard deviation, was higher than expected (generally 8–25% for PAHs, 6–20% for PCBs and less than 18% for TPH with a few very high values, especially for PCBs), but not different from the other intercomparison studies. Difference between liquid- and solid-phase collection in SFE was found to be significant only for more volatile PAH components such as naphthalene and fluorene. For PCBs and TPH, there were some variation in the results obtained with the two trapping methods.

Evaluation of EN 12354 Part 1 and 2 for Nordic Dwelling Houses

Standardised prediction models for airborne and impact sound insulation in buildings are described in EN 12354 part 1 and 2. These models have been evaluated by comparing the predicted and measured sound insulation for common building constructions used in Nordic dwelling houses. In total, more than 200 comparisons were carried out. The standard includes informative annexes on calculation of input data for the prediction models (the sound reduction index of monolithic elements, the normalised impact sound pressure level of homogeneous floor constructions, the vibration reduction index for junctions, etc.). The annexes as well as alternative calculation principles have been evaluated. Calculations based on a few modifications of the informative annexes are recommended for application of the standard in the Nordic countries. For some types of construction like lightweight double leaf walls, floating floors, etc., results of measurements in Nordic laboratories are in most cases used as input data. The obtained accuracy of the predictions is satisfactory for airborne sound insulation and for impact sound insulation of heavy floors vertically.