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Marlborough, MA, United States

Objective: By analyzing and comparing results from a 2008 proficiency test (PT) event to results from a 2003 PT event, we assessed whether laboratories' abilities to detect Escherichia coli (E. coli) O157:H7 had improved in the intervening 5 years. Methods: A proficiency test sample containing E. coli O157:H7 was mailed to participants enrolled in a PT program, and a survey about stool culture screening practices was distributed to laboratories that had submitted a result for the proficiency test sample. Results: In 2008, 85.3% of laboratories detected E. coli O157:H7, compared to 70% of laboratories in 2003. Also, 72.3% of laboratories now screen at least all bloody stools, compared to 49% of laboratories in 2003. Conclusions: Laboratories' abilities to detect E. coli O157:H7 has improved substantially since 2003. However, many laboratories still fail to follow screening recommendations for Shiga toxin-producing E. coli.

Zheng G.-J.,Proficiency
Yejin Fenxi/Metallurgical Analysis | Year: 2014

The advances in technical characteristics of inductively coupled plasma atomic emission spectrometric (ICP-AES) instruments as well as the application of analytical methods in recent years are reviewed. The newly developed instruments usually adopt advanced technologies (such as CCD/CVD or CMOS solid detector, solid digital generator, bi-directional observation with vertical torch tube, high-performance computer, powerful software, spectral fitting of multi-components and high-high flux automatic sampling) and new energy-efficient design philosophy. Therefore, the spectral resolution, analytical stability and speed as well as cost performance are significantly improved. The analytical wavelength and linear range are also expanded. With the development of advanced instruments having advantageous performances and high cost performance, the application of ICP-AES method will be greatly extended. It can be used for the determination of metallic elements and non-metallic elements in inorganic matters. In addition, it is also applicable for the determination of metallic elements and non-metallic elements in organic matters. The application fields are also enlarged. At present, ICP-AES method has become the necessary analysis method in analytical laboratories for metal materials, energy and chemical industry, water quality and environment, and mineral resources. ©, 2014, Central Iron and Steel Research Institute. All right reserved.

Briggs P.,Proficiency
XXI IMEKO World Congress "Measurement in Research and Industry" | Year: 2015

Proficiency testing provides objective evidence of laboratories testing competence. Laboratories quality control procedures can monitor the validity of tests and calibrations undertaken by measuring continuing performance in multiple rounds of a proficiency testing program. Such monitoring will allow laboratories to identify problems, check for testing bias and other trends and review the effectiveness of corrective actions where problems were highlighted by a proficiency test.

Noblett T.,Proficiency
Accreditation and Quality Assurance | Year: 2012

Microbiological testing can be challenging due to the unique nature of microorganisms. Studies have shown that values for reproducibility in microbiology are difficult to establish as they can vary depending upon a number of factors such as the organism under test, the matrix and the test method. The relative lack of consistent data on reproducibility means it can be difficult for providers of microbiology PT schemes to establish a suitable standard deviation for proficiency assessment (σ). Methods for establishing σ are described in BS ISO 13528: 2005, but these are not all appropriate in microbiology, given the lack of available data and the large range of possible variables. Using the robust standard deviation of participant results is not recommended as this can vary greatly from round to round and means that performance is not comparable over time. Use of a fixed standard deviation depends very much on the perception of the PT scheme organiser as to what constitutes fitness-for-purpose. In microbiology, is it really necessary to obtain precise results? Should the emphasis be on the correct isolation and identification of organisms, and on performance over time to detect laboratory bias rather than on enumeration results alone? © 2012 Springer-Verlag.

Noblett T.,Proficiency
Accreditation and Quality Assurance | Year: 2015

Participants taking part in proficiency testing (PT) schemes often question whether the transport conditions, particularly time and temperature, could affect their sample and subsequently their performance scores. This is particularly true for microbiology PT schemes which contain living microorganisms and therefore pose a significant challenge in maintaining stability during a range of different transport conditions. Even though the PT provider can perform stability testing, it is impossible to predict and reproduce all possible environmental conditions that samples could be exposed to during transport. In this study, a number of PT scheme samples were selected in order to observe the effects of transport on the participant results for a range of different microorganisms and matrices. For each microorganism over a number of rounds, the participant results were compared against date of analysis, average distance travelled (km) and average temperature (°C) of destination country in order to determine whether there were any significant trends between participants’ results and the different transport conditions. More than half of participants (62 %) received and tested the PT samples within 4 days of the dispatch date, and 90 % of participants received and tested the samples within 10 days of the dispatch date. Distance travelled by samples ranged from 0 to 16000 km, and the average temperature of destination countries ranged from –10 °C to +25 °C. The results varied by round and microorganism, but overall the date of analysis, distance travelled and average temperature of destination country were not found to have a significant effect on participant results. Even participants from the same country receiving and testing the same sample at the same time could obtain very different results which are therefore unlikely to be due to transport factors. © 2015, Springer-Verlag Berlin Heidelberg.

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