Advances in standardizing and validating research techniques for pathogen monitoring in water

2004 ◽  
Vol 4 (2) ◽  
pp. 23-30
Author(s):  
K. Connell ◽  
M. Pope ◽  
K. Miller ◽  
J. Scheller ◽  
J. Pulz
Keyword(s):  
Validation Studies ◽  
Development Process ◽  
Monitoring Methods ◽  
Microbiological Method ◽  
Validation Process ◽  
Method Performance ◽  
Target Analytes ◽  
Interlaboratory Validation ◽  
Quality Control Criteria ◽  
Control Criteria

Designing and conducting standardized microbiological method interlaboratory validation studies is challenging because most methods are manual, rather than instrument-based, and results from the methods are typically subjective. Determinations of method recovery, in particular, are problematic, due to difficulties in assessing the true spike amount. The standardization and validation process used for the seven most recent USEPA 1600-series pathogen monitoring methods has begun to address these challenges. A staged development process was used to ensure that methods were adequately tested and standardized before resources were dedicated to interlaboratory validation. The interlaboratory validation studies for USEPA Method 1622, for Cryptosporidium, USEPA Method 1601 for coliphage, and USEPA Method 1605 for Aeromonas assessed method performance using different approaches, due the differences in the nature of the target analytes and the data quality needs of each study. However, the use of enumerated spikes in all of the studies allowed method recovery and precision to be assessed, and also provided the data needed to establish quantitative quality control criteria for the methods.

scholarly journals DETECTION OF ACID NEUTRALIZERS IN FRAUDULENT MILK: FULL VALIDATION OF A CLASSICAL QUALITATIVE METHOD

Química Nova ◽  
2021 ◽  
Author(s):  
Carina Gondima ◽  
Marina Palhares ◽  
Pedro Santos ◽  
Roberto Sousa ◽  
Roberto Junqueira ◽  
...  
Keyword(s):  
Sodium Bicarbonate ◽  
Milk Production ◽  
Qualitative Method ◽  
Sodium Citrate ◽  
Raw Milk ◽  
Validation Process ◽  
Method Performance ◽  
Production Chain ◽  
Interlaboratory Validation ◽  
Single Laboratory

Neutralization with alkaline compounds is one of the most common adulterations in milk. The rosolic acid method is a classical test widely used in different countries for detection of neutralizers in milk. The official and a modified version were validated in a single laboratory validation process considering four adulterants: sodium bicarbonate(BI), sodium carbonate(CA), sodium hydroxide(HY) and sodium citrate(CI). The modified version, which presented better performance was selected for interlaboratory validation. In this process, samples of raw milk with acidities of 0.19% were neutralized with different concentrations of BI, CA, HY and C and tested for homogeneity and stability. Eight laboratories, which represented different sectors of the milk production chain, received and analysed these samples. The collaborative trial results confirmed the method performance, although sensitivity and precision were inferior to those obtained in the intralaboratory process, demonstrating its applications and limitations

scholarly journals Quality Control Criteria for Analysis of Organic Traces in Water

2002 ◽  
Vol 2 ◽  
pp. 1040-1043
Author(s):  
José L. Martinez Vidal ◽  
Antonia Garrido Frenich ◽  
Francisco J. Egea González
Keyword(s):  
Quality Control ◽  
Environmental Monitoring ◽  
Organic Contaminants ◽  
Target Analytes ◽  
Quality Control Criteria ◽  
Control Criteria

The aim of this paper is the discussion of quality control (QC) criteria for environmental monitoring of organic contaminants at trace levels in water. In addition, QC criteria in the identification and confirmation of target analytes have been considered.

scholarly journals Evaluating Presence/Absence of Target Microbes in Microbiological Tests

2000 ◽  
Vol 83 (6) ◽  
pp. 1429-1434
Author(s):  
Robert J Blodgett ◽  
Anthony D Hitchins
Keyword(s):  
Performance Studies ◽  
Collaborative Study ◽  
False Negative ◽  
The Other ◽  
Test Results ◽  
Logistic Curve ◽  
Microbiological Method ◽  
Test Portion ◽  
Method Performance ◽  
Data Set

Abstract A typical qualitative microbiological method performance (collaborative) study gathers a data set of responses about a test for the presence or absence of a target microbe. We developed 2 models that estimate false-positive and false-negative rates. One model assumes a constant probability that the tests will indicate the target microbe is present for any positive concentration in the test portion. The other model assumes that this probability follows a logistic curve. Test results from several method performance studies illustrate these estimates.

scholarly journals Assessment of SARS-CoV-2 genome sequencing: quality criteria and low frequency variants

2021 ◽  
Author(s):  
Damien Jacot ◽  
Trestan Pillonel ◽  
Gilbert Greub ◽  
Claire Bertelli
Keyword(s):  
Sample Selection ◽  
Low Frequency ◽  
Pcr Amplification ◽  
Quality Criterion ◽  
Quality Criteria ◽  
Sequencing Errors ◽  
Sequencing Quality ◽  
Quality Control Criteria ◽  
Control Criteria ◽  
Sequence Quality

Although many laboratories worldwide have developed their sequencing capacities in response to the need for SARS-CoV-2 genome-based surveillance of variants, only few reported some quality criteria to ensure sequence quality before lineage assignment and submission to public databases. Hence, we aimed here to provide simple quality control criteria for SARS-CoV-2 sequencing to prevent erroneous interpretation of low quality or contaminated data. We retrospectively investigated 647 SARS-CoV-2 genomes obtained over ten tiled amplicons sequencing runs. We extracted 26 potentially relevant metrics covering the entire workflow from sample selection to bioinformatics analysis. Based on data distribution, critical values were established for eleven selected metrics to prompt further quality investigations for problematic samples, in particular those with a low viral RNA quantity. Low frequency variants (<70% of supporting reads) can result from PCR amplification errors, sample cross contaminations or presence of distinct SARS-CoV2 genomes in the sample sequenced. The number and the prevalence of low frequency variants can be used as a robust quality criterion to identify possible sequencing errors or contaminations. Overall, we propose eleven metrics with fixed cutoff values as a simple tool to evaluate the quality of SARS-CoV-2 genomes, among which cycle thresholds, mean depth, proportion of genome covered at least 10x and the number of low frequency variants combined with mutation prevalence data.

scholarly journals Determination of Fumonisins B1 and B2 in Corn by LC/MS with Immunoaffinity Column Cleanup: Interlaboratory Study

2010 ◽  
Vol 93 (2) ◽  
pp. 611-621 ◽  
Author(s):  
Hamide Z Senyuva ◽  
John Gilbert ◽  
Joerg Stroka ◽  
S Biselli ◽  
A De Girolamo ◽  
...  
Keyword(s):  
Fine Powder ◽  
Immunoaffinity Column ◽  
Selected Ion Monitoring ◽  
Test Portion ◽  
Method Performance ◽  
Three Samples ◽  
Interlaboratory Validation ◽  
Cleanup Procedure ◽  
Phosphate Buffered Saline

Abstract An interlaboratory validation study was conducted to establish the method performance characteristics of an immunoaffinity column (IAC) cleanup procedure followed by LC/MS for the determination of fumonisins B1 (FB1) and B2 (FB2) and combined FB1 + FB2 in corn. The test portion is extracted with acetonitrilemethanolwater (25 + 25 + 50). The extract is filtered, diluted with phosphate-buffered saline solution, and applied to an IAC. FB1 and FB2 are removed with methanol, followed by water, then directly determined by RPLC with MS detection using selected-ion monitoring of two characteristic ions in each case. Naturally contaminated corn samples were milled to a fine powder and mixed to produce three samples with target levels of combined FB1 + FB2 ranging from 350 to 4000 g/kg. Of 15 initially participating laboratories, two failed to report results and another did not follow the prescribed method. Thus, valid results were obtained from 12 participants located in 11 countries. Statistical analysis of the results produced RSDr values of 4.611.9, 1.912.6, and 1.411.5 for FB1, FB2, and combined FB1 + FB2, respectively; the corresponding RSDR values were 19.823.8, 18.225.5, and 18.823.2. The three concentration levels of combined FB1 + FB2 were 534, 1194, and 1954 g/kg. HorRat values for r and R were all &lt;2.0, indicating that the method is suitable as a regulatory method for the enforcement of European Union limits for fumonisins in corn.

Lost In Translation

2008 ◽  
pp. 366-379
Author(s):  
Eddy Boot ◽  
Jon Nelson ◽  
Daniela De Faveri
Keyword(s):  
Validation Studies ◽  
Development Process ◽  
3D Model ◽  
Level Of Detail ◽  
Instructional Software ◽  
Instructional Designers ◽  
Design Languages ◽  
Design Documents ◽  
Lost In Translation ◽  
Precise Expression

Developing modern instructional software has become very complex. As a result, the communication between instructional designers and other stakeholders in the development process is becoming increasingly important. However, due to differences in background, focus, and tools among ISD stakeholders instructional designers lack the means to provide reasonably unequivocal design documentation for these stakeholders. These differences in stakeholders create a context where the design documents produced are not sufficiently related to the specific needs of the stakeholders, in terms of meaningful organization and differentiation of level of detail. This problem is complicated by the lack of shared design languages. These problems prevent precise expression of design information. The 3D-model is introduced to support instructional designers to stratify, elaborate, and formalize design documents, even if design languages are hardly shared between designers and other stakeholders. Two validation studies show that the 3D-model contributes to a better information transition between instructional designers and software producers—one of the stakeholders in the development process.

scholarly journals Problems and practical considerations in assessing accuracy with NIST SRM 909a: report of defective vials

1996 ◽  
Vol 42 (11) ◽  
pp. 1832-1837 ◽  
Author(s):  
B K De ◽  
B A Karr ◽  
S Ghosn ◽  
B E Copeland
Keyword(s):  
Monitoring Program ◽  
Experimental Period ◽  
Medical Monitoring ◽  
Electron Microscopic ◽  
Value Analysis ◽  
Assigned Value ◽  
Technology Standard ◽  
Quality Control Criteria ◽  
Glucose Recovery ◽  
Control Criteria

Abstract During an experimental period of 12 months in 1992-1993, while we were comparing the effectiveness of monthly vs quarterly use of the National Institute for Standards and Technology Standard Reference Material (NIST SRM) 909a as an accuracy material for the projected 30-year Fernald Medical Monitoring Program, we encountered three random defective vials with a glucose recovery of less than 30% of the NIST-assigned value. Analysis with five different multichannel instruments confirmed the original finding. Concomitant glucose recovery from adjacent vials was 97%-104%, as determined by using the same instruments, reagents, calibrators, and quality-control criteria on the same days. Recoveries of uric acid and cholesterol were also low (53-75% and 75-80%, respectively) in the three defective vials. Other analytes were unaffected. Studies to identify the cause of the defective vials were carried out with microbiological, electron microscopic, and biochemical techniques. When used for accuracy studies, each vial of NIST SRM 909a should have a concomitant check for glucose recovery to detect whether the vial is defective.

scholarly journals Oscillometric and Spirometric Bronchodilator Response in Preschool Children with and without Asthma

2012 ◽  
Vol 19 (4) ◽  
pp. 273-277 ◽  
Author(s):  
Youn Ho Shin ◽  
Sun Jung Jang ◽  
Jung Won Yoon ◽  
Hye Mi Jee ◽  
Sun Hee Choi ◽  
...  
Keyword(s):  
Preschool Children ◽  
Forced Vital Capacity ◽  
Vital Capacity ◽  
Forced Expiratory Volume ◽  
Bronchodilator Response ◽  
Asthmatic Children ◽  
Before And After ◽  
Forced Expiratory Flow ◽  
Quality Control Criteria ◽  
Control Criteria

BACKGROUND: Bronchodilator responses (BDR) are routinely used in the diagnosis and management of asthma; however, their acceptability and repeatability have not been evaluated using quality control criteria for preschool children.OBJECTIVES: To compare conventional spirometry with an impulse oscillometry system (IOS) in healthy and asthmatic preschool children.METHODS: Data from 30 asthmatic children and 29 controls (two to six years of age) who underwent IOS and spirometry before and after salbutamol administration were analyzed.RESULTS: Stable asthmatic subjects significantly differed versus controls in their spirometry-assessed BDR (forced expiratory volume in 1 s [FEV1], forced vital capacity and forced expiratory flow at 25% to 75% of forced vital capacity) as well as their IOS-assessed BDR (respiratory resistance at 5 Hz [Rrs5], respiratory reactance at 5 Hz and area under the reactance curve). However, comparisons based on the area under the ROC curve for ΔFEV1% initial versus ΔRrs5% initial were 0.82 (95% CI 0.71 to 0.93) and 0.75 (95% CI 0.62 to 0.87), respectively. Moreover, the sensitivity and specificity for ΔFEV1≥9% were 0.53 and 0.93, respectively. Importantly, sensitivity increased to 0.63 when either ΔFEV1≥9% or ΔRrs5≥29% was considered as an additional criterion for the diagnosis of asthma.CONCLUSION: The accuracy of asthma diagnosis in preschool children may be increased by combining spirometry with IOS when measuring BDR.

Human resources ranking in a cloud-based knowledge sharing framework using the quality control criteria

Kybernetes ◽  
2017 ◽  
Vol 46 (5) ◽  
pp. 876-892 ◽  
Author(s):  
Parisa Fouladi ◽  
Nima Jafari Navimipour
Keyword(s):  
Quality Control ◽  
Human Resources ◽  
Hierarchical Structure ◽  
Simple Method ◽  
Content Type ◽  
Quality Control Criteria ◽  
Control Criteria ◽  
Selection Of

Purpose This paper aims to propose a new method for evaluating the quality and prioritizing of the human resources (HRs) based on trust, reputation, agility, expertise and cost criteria in the expert cloud. To evaluate some quality control (QC) factors, a model based on the SERVQUAL is used. Design/methodology/approach The aim of this paper is to offer a fast and simple method for selecting the HRs by the customers. To achieve this goal, the ranking diagram of different HRs based on the different criteria of QC is provided. By means of this method, the customer can rapidly decide on the selection of the required HRs. By using the proposed method, the scores for various criteria are evaluated. These criteria are used in the ranking of each HR which is obtained based on the evaluation conducted by previous customers and their colleagues. First, customers were asked to select their needed criteria and then by constructing a hierarchical structure, the ranking diagram of different HRs is achieved. Using a ranking system based on evaluating the quality of the model, satisfy the customer needs to be based on the properties of HRs. Also, an analytical hierarchical process-based ranking mechanism is proposed to solve the problem of assigning weights to features for considering the interdependence between them to rank the HRs in the expert cloud. Findings The obtained results showed the applicability of the radar graph using a case study and also numerically obtained results showed that a hierarchical structure increases the quality and speed rating of HR ranking than the previous works. Originality/value The suggested ranking method in this paper allows the optimal selection due to the special needs of any given customer in the expert cloud.

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