scholarly journals Comparison of duplicate portion and 24 h recall as reference methods for validating a FFQ using urinary markers as the estimate of true intake

2015 ◽  
Vol 114 (8) ◽  
pp. 1304-1312 ◽  
Author(s):  
Laura Trijsburg ◽  
Jeanne H. M. de Vries ◽  
Hendriek C. Boshuizen ◽  
Paul J. M. Hulshof ◽  
Peter C. H. Hollman ◽  
...  
Keyword(s):  
Measurement Error ◽  
Validation Study ◽  
Reference Method ◽  
Bias Error ◽  
Correlated Errors ◽  
Web Based ◽  
Urinary Markers ◽  
Reference Methods ◽  
Duplicate Portion ◽  
Better Than

AbstractAs FFQ are subject to measurement error, associations between self-reported intake by FFQ and outcome measures should be adjusted by correction factors obtained from a validation study. Whether the correction is adequate depends on the characteristics of the reference method used in the validation study. Preferably, reference methods should (1) be unbiased and (2) have uncorrelated errors with those in the FFQ. The aim of the present study was to assess the validity of the duplicate portion (DP) technique as a reference method and compare its validity with that of a commonly used reference method, the 24 h recall (24hR), for protein, K and Na using urinary markers as the unbiased reference method. For 198 subjects, two DP, two FFQ, two urinary biomarkers and between one and fifteen 24hR (web based and/or telephone based) were collected within 1·5 years. Multivariate measurement error models were used to estimate bias, error correlations between FFQ and DP or 24hR, and attenuation factors of these methods. The DP was less influenced by proportional scaling bias (0·58 for protein, 0·72 for K and 0·52 for Na), and correlated errors between DP and FFQ were lowest (protein 0·28, K 0·17 and Na 0·19) compared with the 24hR. Attenuation factors (protein 0·74, K 0·54 and Na 0·43) also indicated that the DP performed better than the 24hR. Therefore, the DP is probably the best available reference method for FFQ validation for nutrients that currently have no generally accepted recovery biomarker.

scholarly journals In-House Validation Study of the DuPont Qualicon BAX System Q7 Instrument with the BAX System PCR Assay for Salmonella (Modification of AOAC Official MethodSM 2003.09 and AOAC Research Institute Performance-Tested MethodSM 100201)

2009 ◽  
Vol 92 (3) ◽  
pp. 989-994 ◽  
Author(s):  
George Tice ◽  
Bridget Andaloro ◽  
H Kirk White ◽  
Lance Bolton ◽  
Siqun Wang ◽  
...  
Keyword(s):  
Validation Study ◽  
Reference Method ◽  
Pcr Assay ◽  
Paired Samples ◽  
Reference Methods ◽  
Comparable Performance ◽  
Aoac Official ◽  
Inspection Service ◽  
Positive Results ◽  
The U.S

Abstract In 2006, DuPont Qualicon introduced the BAX<sup/> system Q7 instrument for use with its assays. To demonstrate the equivalence of the new and old instruments, a validation study was conducted using the BAX system PCR Assay for Salmonella, AOAC Official MethodSM 2003.09, on three food types. The foods were simultaneously analyzed with the BAX system Q7 instrument and either the U.S. Food and Drug Administration Bacteriological Analytical Manual or the U.S. Department of AgricultureFood Safety and Inspection Service Microbiology Laboratory Guidebook reference method for detecting Salmonella. Comparable performance between the BAX system and the reference methods was observed. Of the 75 paired samples analyzed, 39 samples were positive by both the BAX system and reference methods, and 36 samples were negative by both the BAX system and reference methods, demonstrating 100 correlation. Inclusivity and exclusivity for the BAX system Q7 instrument were also established by testing 50 Salmonella strains and 20 non-Salmonella isolates. All Salmonella strains returned positive results, and all non-Salmonella isolates returned a negative response.

scholarly journals Associations between reported intakes of carotenoid-rich foods and concentrations of carotenoids in plasma: a validation study of a web-based food recall for children and adolescents

2016 ◽  
Vol 19 (18) ◽  
pp. 3265-3275 ◽  
Author(s):  
Anine Christine Medin ◽  
Monica Hauger Carlsen ◽  
Lene Frost Andersen
Keyword(s):  
Children And Adolescents ◽  
Validation Study ◽  
Plasma Concentrations ◽  
Rank Correlation ◽  
Reference Method ◽  
Cross Sectional ◽  
Web Based ◽  
Cross Classification ◽  
Food Recall ◽  
Β Carotene

AbstractObjectiveTo validate estimated intakes of carotenoid-rich foods from a web-based food recall (WebFR) using carotenoids in blood as an objective reference method.DesignCross-sectional validation study using carotenoids in plasma to evaluate estimated intakes of selected carotenoid-rich foods. Participants recorded their food intake in the WebFR and plasma concentrations of β-carotene, α-carotene, β-cryptoxanthin, lycopene, lutein and zeaxanthin were measured.SettingSchools and homes of families in a suburb of the capital of Norway.SubjectsA total of 261 participants in the age groups 8–9 and 12–14 years.ResultsSpearman’s rank correlation coefficients ranged from 0·30 to 0·44, and cross-classification showed that 71·6–76·6 % of the participants were correctly classified, when comparing the reported intakes of carotenoid-rich foods and concentrations of the corresponding carotenoids in plasma, not including lutein and zeaxanthin.ConclusionsCorrelations were acceptable and cross-classification analyses demonstrated that the WebFR was able to rank participants according to their reported intake of foods rich in α-carotene, β-carotene, β-cryptoxanthin and lycopene. The WebFR is a promising tool for dietary assessment among children and adolescents.

scholarly journals A Method to adjust for measurement error in multiple exposure variables measured with correlated errors in the absence of an internal validation study

F1000Research ◽  
2020 ◽  
Vol 9 ◽  
pp. 1486
Author(s):  
Alexander K. Muoka ◽  
George O. Agogo ◽  
Oscar O. Ngesa ◽  
Henry G. Mwambi
Keyword(s):  
Sensitivity Analysis ◽  
Measurement Error ◽  
Validation Study ◽  
Real Data ◽  
Epidemiological Studies ◽  
Correlated Errors ◽  
Internal Validation ◽  
Multivariate Method ◽  
Multiple Exposures ◽  
Naive Method

Difficulty in obtaining the correct measurement for an individual’s longterm exposure is a major challenge in epidemiological studies that investigate the association between exposures and health outcomes. Measurement error in an exposure biases the association between the exposure and a disease outcome. Usually, an internal validation study is required to adjust for exposure measurement error; it is challenging if such a study is not available. We propose a general method for adjusting for measurement error where multiple exposures are measured with correlated errors (a multivariate method) and illustrate the method using real data. We compare the results from the multivariate method with those obtained using a method that ignores measurement error (the naive method) and a method that ignores correlations between the errors and true exposures (the univariate method). It is found that ignoring measurement error leads to bias and underestimates the standard error. A sensitivity analysis shows that the magnitude of adjustment in the multivariate method is sensitive to the magnitude of measurement error, sign, and the correlation between the errors. We conclude that the multivariate method can be used to adjust for bias in the outcome-exposure association in a case where multiple exposures are measured with correlated errors in the absence of an internal validation study. The method is also useful in conducting a sensitivity analysis on the magnitude of measurement error and the sign of the error correlation.

scholarly journals Validating fatty acid intake as estimated by an FFQ: how does the 24 h recall perform as reference method compared with the duplicate portion?

2018 ◽  
Vol 21 (14) ◽  
pp. 2568-2574
Author(s):  
Laura Trijsburg ◽  
Jeanne HM de Vries ◽  
Peter CH Hollman ◽  
Paul JM Hulshof ◽  
Pieter van ’t Veer ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Fatty Acid ◽  
Linoleic Acid ◽  
Measurement Error ◽  
Chemical Analysis ◽  
Reference Method ◽  
Fatty Acid Intake ◽  
Acid Intake ◽  
Duplicate Portion ◽  
Estimate Validity

AbstractObjectiveTo compare the performance of the commonly used 24 h recall (24hR) with the more distinct duplicate portion (DP) as reference method for validation of fatty acid intake estimated with an FFQ.DesignIntakes of SFA, MUFA, n-3 fatty acids and linoleic acid (LA) were estimated by chemical analysis of two DP and by on average five 24hR and two FFQ. Plasma n-3 fatty acids and LA were used to objectively compare ranking of individuals based on DP and 24hR. Multivariate measurement error models were used to estimate validity coefficients and attenuation factors for the FFQ with the DP and 24hR as reference methods.SettingWageningen, the Netherlands.SubjectsNinety-two men and 106 women (aged 20–70 years).ResultsValidity coefficients for the fatty acid estimates by the FFQ tended to be lower when using the DP as reference method compared with the 24hR. Attenuation factors for the FFQ tended to be slightly higher based on the DP than those based on the 24hR as reference method. Furthermore, when using plasma fatty acids as reference, the DP showed comparable to slightly better ranking of participants according to their intake of n-3 fatty acids (0·33) and n-3:LA (0·34) than the 24hR (0·22 and 0·24, respectively).ConclusionsThe 24hR gives only slightly different results compared with the distinctive but less feasible DP, therefore use of the 24hR seems appropriate as the reference method for FFQ validation of fatty acid intake.

scholarly journals Validation Study of a Rapid ELISA for Detection of Deoxynivalenol in Wheat, Barley, Malted Barley, Corn, Oats, and Rice

2010 ◽  
Vol 93 (2) ◽  
pp. 600-610 ◽  
Author(s):  
Anthony Lupo ◽  
Chris Roebuck ◽  
Ken Settimo ◽  
Anna Quain ◽  
Justina Kennedy ◽  
...  
Keyword(s):  
Rapid Method ◽  
Electron Capture ◽  
Validation Study ◽  
Reference Method ◽  
Elisa Test ◽  
Electron Capture Detection ◽  
Reference Methods ◽  
Test Kit ◽  
Aoac Official ◽  
Research Institute

Abstract Neogen Corp. developed the Veratox DON test kit for the detection of deoxynivalenol (DON). The purpose of this study was to validate the method under the requirements of the AOAC Research Institute Performance Tested MethodsSM (PTM) program. There are two AOAC Official MethodsSM for DON detection: 986.17 and 986.18, the first of which is a TLC method and the second a GC method. A rapid method (PTM 000701) has also been performance tested by the AOAC Research Institute. One of the most widely used reference methods; however, is a GC method with electron capture detection that is referred to as the reference method in this paper. Although considered the reference method, the GC procedure is complicated and requires the investment of both expensive equipment and a highly skilled technician. A rapid (e.g., ELISA) test kit needs to be validated by the AOAC Research Institute. The Veratox 2/3 method is highly reproducible with average CV values <10, and is very accurate, showing >97 correlation to reference methods.

scholarly journals A Method to Adjust for Measurement Error in Three Exposures Measured with Correlated Errors in the Absence of Internal Validation Study

2019 ◽  
Author(s):  
Alexander K. Muoka ◽  
George Agogo ◽  
Oscar Ngesa ◽  
Henry Mwambi
Keyword(s):  
Measurement Error ◽  
Validation Study ◽  
Real Data ◽  
Epidemiological Studies ◽  
Correlated Errors ◽  
Exposure Measurement ◽  
Internal Validation ◽  
Exposure Measurement Error ◽  
Correlated Exposures

Abstract Difficulty in obtaining the correct measurement for an individual's long-term exposure is a major challenge in epidemiological studies that investigate the association between exposures and health outcomes. Measurement error in an exposure biases the association between the exposure and a disease outcome. Usually an internal validation study is required to adjust for exposure measurement error; it is challenging if such a study is not available. We proposed a method (trivariate method) that adjusts for measurement error in three correlated exposures in the absence of internal validation study and illustrated the method using real data. We compared the results from the proposed method with those obtained using a method that ignores measurement error and a method that ignores correlations between the errors and true exposures (the univariate method). It was found that ignoring measurement error leads to bias and underestimates the standard error. It was also found that the magnitude of adjustment in the trivariate method is sensitive to the magnitude of measurement error, sign and correlation between the errors. We conclude that the proposed method can be used to adjust for bias in the outcome-exposure association in a case where three exposures are measured with correlated errors in the absence of an internal validation study. The method is useful in conducting a sensitivity analysis on the magnitude of measurement error and the sign of the error correlation.

Comparison of approaches to correct intake–health associations for FFQ measurement error using a duplicate recovery biomarker and a duplicate 24 h dietary recall as reference method

2014 ◽  
Vol 18 (2) ◽  
pp. 226-233 ◽  
Author(s):  
Anouk Geelen ◽  
Olga W Souverein ◽  
Maria C Busstra ◽  
Jeanne HM de Vries ◽  
Pieter van ‘t Veer
Keyword(s):  
Measurement Error ◽  
Gold Standard ◽  
Reference Method ◽  
Correlated Errors ◽  
Dietary Recall ◽  
Validity Coefficient ◽  
Small Correction ◽  
Gold Standard Reference ◽  
The Impact ◽  
Do So

AbstractObjectiveTo illustrate the impact of intake-related bias in FFQ and 24 h recall (24hR), and correlated errors between these methods, on intake–health associations.DesignDietary intake was assessed by a 180-item semi-quantitative FFQ and two 24hR. Urinary N and urinary K were estimated from two 24 h urine samples. We compared four scenarios to correct associations for errors in an FFQ estimating protein and K intakes.SettingWageningen, The Netherlands.SubjectsFifty-nine men and fifty-eight women aged 45–65 years.ResultsFor this FFQ, measurement error weakened a true relative risk of 2·0 to 1·4 for protein and 1·5 for K. As compared with calibration to duplicate recovery biomarkers (i.e. the preferred scenario 1), estimating a validity coefficient using this duplicate biomarker resulted in overcorrected associations, caused by intake-related bias in the FFQ (scenario 2). The correction factor based on a triad using biomarkers and 24hR was hampered by this intake-related bias and by correlated errors between FFQ and 24hR, and in this population resulted in a nearly perfect correction for protein but an overcorrection for K (scenario 3). When the 24hR was used for calibration, only a small correction was done, due to correlated errors between the methods and intake-related bias in the 24hR (scenario 4).ConclusionsCalibration to a gold standard reference method is the preferred approach to correct intake–health associations for FFQ measurement error. If it is not possible to do so, using the 24hR as reference method only partly removes the errors, but may result in improved intake–health associations.

scholarly journals Applicability and performance of EUCAST’s rapid antimicrobial susceptibility testing (RAST) on primarily sterile body fluids in blood culture bottles in laboratory routine with total lab automation

2021 ◽  
Author(s):  
Jasmin Kaur Jasuja ◽  
Stefan Zimmermann ◽  
Irene Burckhardt
Keyword(s):  
Blood Culture ◽  
Susceptibility Testing ◽  
Reference Method ◽  
Body Fluids ◽  
E Coli ◽  
Mueller Hinton ◽  
Mueller Hinton Agar ◽  
And Performance ◽  
Sterile Body Fluids ◽  
Better Than

AbstractOptimisation of microbiological diagnostics in primarily sterile body fluids is required. Our objective was to apply EUCAST’s RAST on primarily sterile body fluids in blood culture bottles with total lab automation (TLA) and to compare results to our reference method Vitek2 in order to report susceptibility results earlier. Positive blood culture bottles (BACTEC™ Aerobic/Anaerobic/PEDS) inoculated with primarily sterile body fluids were semi-automatically subcultured onto Columbia 5% SB agar, chocolate agar, MacConkey agar, Schaedler/KV agar and Mueller-Hinton agar. On latter, cefoxitin, ampicillin, vancomycin, piperacillin/tazobactam, meropenem and ciprofloxacin were added. After 6 h, subcultures and RAST were imaged and MALDI-TOF MS was performed. Zone sizes were digitally measured and interpreted following RAST breakpoints for blood cultures. MIC values were determined using Vitek2 panels. During a 1-year period, 197 Staphylococcus aureus, 91 Enterococcus spp., 38 Escherichia coli, 11 Klebsiella pneumoniae and 8 Pseudomonas aeruginosa were found. Categorical agreement between RAST and MIC was 96.5%. Comparison showed no very major errors, 2/7 (28.6%) and 1/7 (14.3%) of major errors for P. aeruginosa and meropenem and ciprofloxacin, 1/9 (11.1%) for K. pneumoniae and ciprofloxacin, 4/69 (7.0%) and 3/43 (5.8%) for Enterococcus spp. and vancomycin and ampicillin, respectively. Minor errors for P. aeruginosa and meropenem (1/8; 12.8%) and for E. coli and ciprofloxacin (2/29; 6.5%) were found. 30/550 RAST measurements were within area of technical uncertainty. RAST is applicable and performs well for primarily sterile body fluids in blood culture bottles, partially better than blood-based RAST. Official EUCAST evaluation is needed.

Web-Based Two-Tier Diagnostic Test and Remedial Learning Experiment

2010 ◽  
Vol 8 (1) ◽  
pp. 31-53 ◽  
Author(s):  
Ah-Fur Lai ◽  
Deng-Jyi Chen
Keyword(s):  
Diagnostic Test ◽  
Test Theory ◽  
Multimedia Technology ◽  
Learning Effects ◽  
Web Based ◽  
Test Items ◽  
Electro Magnetic ◽  
Experimental Group ◽  
Northern Taiwan ◽  
Better Than

Offering a series of diagnosis and individual remedial learning activities for a general class by means of web and multimedia technology can overcome the dilemma of conventional diagnosis and remedial instruction. The study proposes a three-layer conceptual framework and adopts a two-tier diagnostic test theory to develop a web-based two-tier diagnostic test and remedial learning management system called “the Dr. System.” The study also designs the two-tier diagnostic test items of electro-magnetic concepts and the related multimedia remedial learning materials based on the theory of modular course for the purpose of investigating the remedial learning effects. In addition, the study helps the participants eliminate their misconception through a quasi-experiment at an elementary school in a metropolitan area of northern Taiwan. The results show that the learners of the experimental group who received the treatment under the Dr. System performed significantly better than those who took the traditional remedial class. The study also indicates that the web-based two-tier diagnostic test helps us understand learners’ misconceptions. As a result, it also provides learners useful remedial multimedia materials, which are necessary for them to eliminate their individual misconceptions in the remedial learning process.

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