scholarly journals Ecotoxicological testing of sediments and dredged material: an overlooked opportunity?

2020 ◽  
Vol 20 (12) ◽  
pp. 4218-4228 ◽  
Author(s):  
Susanne Heise ◽  
Marc Babut ◽  
Carmen Casado ◽  
Ute Feiler ◽  
Benoit J. D. Ferrari ◽  
...  
Keyword(s):  
False Negative ◽  
Added Value ◽  
Management Decision ◽  
Dredged Material ◽  
Negative Results ◽  
False Negative Results ◽  
Management Decision Making ◽  
Chemical Sediment ◽  
The Cost

Abstract Purpose Basing decisions for the management of contaminated sediments on ecotoxicological data is still often met with skepticism by European stakeholders. These concerns are discussed as they pertain to bioassays to show how ecotoxicological data may provide added value for the sustainable management of sediment in aquatic systems. Materials and methods Five “concerns” are selected that are often raised by stakeholders. The ecotoxicological practice is discussed in light of the knowledge gained in recent decades and compared with chemical sediment analysis and chemical data. Results and discussion Common assumptions such as a higher uncertainty of biotest results for sediments compared to chemical analyses are not supported by interlaboratory comparisons. Some confusion also arises, because the meaning of biotest data is often misunderstood, questioning their significance in light of a limited number of organisms and altered test conditions in the lab. Because biotest results describe a sediment property, they should not be directly equated with an impact upon the biological community. To identify a hazard, however, the possibility of false-negative results due to the presence of contaminants that are not analyzed but are toxic is lower. Conclusions The cost of increased investment in ecotoxicological tests is, in our view, small compared with that of making false-negative assessments of sediment/dredged material that can ultimately have long-term environmental costs. As such, we conclude that ecotoxicological testing is an opportunity for sediment management decision-making that warrants more attention and confidence in Europe.

Preenrichment Conditions for Effective Recovery of Salmonella in Foods and Feed Ingredients

1979 ◽  
Vol 42 (2) ◽  
pp. 153-157 ◽  
Author(s):  
J. Y. D'AOUST ◽  
C. MAISHMENT
Keyword(s):  
Brilliant Green ◽  
False Negative ◽  
Food Samples ◽  
Contamination Level ◽  
Experimental Conditions ◽  
Feed Ingredients ◽  
Selective Enrichment ◽  
Negative Results ◽  
False Negative Results ◽  
The Cost

The efficacy of Clausen, EE, Eugon, GN, Tergitol 7, lactose and nutrient broths as Salmonella preenrichment media was evaluated using 165 food samples with an incident contamination level ranging from 1.5 to 460 salmonellae/100 g. Replicate food samples (100 g) were preenriched in each of seven media (900 ml) for 6 h and 24 h at 35 C; various amounts (10, 1.0 and 0.1 ml) of preenriched cultures were selectively enriched in tetrathionate brilliant green (43 C) and selenite cystine (35 C) broths and plated on bismuth sulfite and brilliant green sulfa agars. Short (6 h) and 24-h preenrichment conditions resulted in 26 (16%) and 8 (5%) false negative results, respectively. Recovery of Salmonella from 6-h but not 24-h preenrichment cultures also varied directly with the portion of culture inoculated into selective enrichment broths. None of the preenrichment media tested performed satisfactorily at 6 h of incubation where levels of recovery ranged from 32 to 62%; at 24 h, good recovery was obtained with all media (95 to 100%) except EE broth (74%). The incidence of competitive flora was significantly higher on selenite + brilliant green sulfa than on tetrathionate + bismuth sulfite; transfer volumes (10 and 1.0 ml) and preenrichment media did not contribute significantly to the presence of non-salmonellae on plating media. Characteristics of preenrichment media were found to be less critical than preenrichment incubation time for effective recovery of Salmonella in foods and feed ingredients. The use of 1.0- rather than 10-ml preenrichment transfer volume is indicated because it proved to be completely reliable under our experimental conditions and reduced the cost of analyses.

scholarly journals 667. Next Generation Sequencing of Microbial Cell Free DNA in the Diagnosis and Treatment of Infectious Disease in Children: When Does the Result Justify the Cost?

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S436-S436
Author(s):  
Rachel Downey Quick ◽  
Kelli A Martinez ◽  
Susan M Russo ◽  
Sarah E McGwier ◽  
Rachel A Quirt ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
Antimicrobial Resistance ◽  
False Negative ◽  
Next Generation ◽  
Cell Free Dna ◽  
Negative Results ◽  
Free Dna ◽  
False Negative Results ◽  
The Cost ◽  
Generation Sequencing

Abstract Background Pathogen testing using next-generation sequencing of microbial cell-free DNA (NGS cfDNA) is a promising diagnostic tool to identify pathogens that might not be detected using conventional lab evaluation. Considering the cost of this test, it is important to determine when it is most useful to the plan of care (POC). Figure 1. Unit of admission among cases Figure 2. Patient characteristics in cases determined to be valuable and not valuable to the plan of care (POC) Methods In this retrospective study, we collected data from the medical charts of 50 consecutive NGS cfDNA tests in a free-standing children’s hospital. We evaluated patients for demographics, underlying conditions, diagnosis at time of testing, conventional laboratory testing and timing, medical treatment, and NGS cfDNA test results for clinical relevance or false negative results compared to conventional testing. The primary goal was to identify patients for whom the NGS cfDNA testing affected the POC. Charts were reviewed, and determinations regarding whether the result influenced the POC were confirmed by a provider. Results We were unable to differentiate patients with clinically valuable NGS cfDNA results (Fig 1 & 2). Among those with NGS cfDNA results valuable to the POC (n=22), both negative and positive testing guided POC (13 valuable negative vs. 9 diagnostic cases). In the total sample, 5 cases (10%) had a clinically relevant pathogen identified through conventional testing, but not through NGS cfDNA and 2 cases had antimicrobial resistance on culture, which is not detected by NGS cfDNA. Conclusion While we did not find a specific clinical profile for NGS cfDNA use, positive results were essential to the diagnosis in 18% of cases with otherwise negative laboratory evaluation for the pathogen identified in NGS cfDNA. Negative tests affected the POC in 26% of cases by avoiding unnecessary antimicrobials in high risk immunocompromised patients and patients that presented with low-risk of infection, but unclear disease process. Caution must be exercised with reliance on this test with respect to antimicrobial resistance and risk of false negative results. Disclosures All Authors: No reported disclosures

scholarly journals Modelling the epidemiology of malaria and spread of HRP2-negative Plasmodium falciparum following the replacement of HRP2-detecting rapid diagnostic tests

2022 ◽  
Vol 2 (1) ◽  
pp. e0000106
Author(s):  
Alisha Chaudhry ◽  
Jane Cunningham ◽  
Qin Cheng ◽  
Michelle L. Gatton
Keyword(s):  
Plasmodium Falciparum ◽  
Diagnostic Tests ◽  
False Negative ◽  
Parasite Prevalence ◽  
Rapid Diagnostic Tests ◽  
Negative Results ◽  
False Negative Results ◽  
Malaria Rapid Diagnostic Tests ◽  
The Impact

Malaria rapid diagnostic tests (RDTs) are dominated by products which use histidine-rich protein 2 (HRP2) to detect Plasmodium falciparum. The emergence of parasites lacking the pfhrp2 gene can lead to high rates of false-negative results amongst these RDTs. One solution to restore the ability to correctly diagnose falciparum malaria is to switch to an RDT which is not solely reliant on HRP2. This study used an agent-based stochastic simulation model to investigate the impact on prevalence and transmission caused by switching the type of RDT used once false-negative rates reached pre-defined thresholds within the treatment-seeking symptomatic population. The results show that low transmission settings were the first to reach the false-negative switch threshold, and that lower thresholds were typically associated with better long-term outcomes. Changing the diagnostic RDT away from a HRP2-only RDT is predicted to restore the ability to correctly diagnose symptomatic malaria infections, but often did not lead to the extinction of HRP2-negative parasites from the population which continued to circulate in low density infections, or return to the parasite prevalence and transmission levels seen prior to the introduction of the HRP2-negative parasite. In contrast, failure to move away from HRP2-only RDTs leads to near fixation of these parasites in the population, and the inability to correctly diagnose symptomatic cases. Overall, these results suggest pfhrp2-deleted parasites are likely to become a significant component of P. falciparum parasite populations, and that long-term strategies are needed for diagnosis and surveillance which do not rely solely on HRP2.

scholarly journals Non-specific Primers Reveal False-negative Risk in Detection of COVID-19

2020 ◽  
Author(s):  
Wei Liu
Keyword(s):  
False Negative ◽  
Hubei Province ◽  
Added Value ◽  
High Abundance ◽  
Rt Pcr ◽  
Specific Primers ◽  
Cathepsin C ◽  
Negative Results ◽  
False Negative Results ◽  
Negative Detection

SummaryBackgroundA novel coronavirus disease 2019 (COVID-19) broke out in Wuhan of Hubei province and had spread throughout the world since December 2019. Because the clinically diagnosed cases in Hubei province were reported for the first time on February 13, 2020, a very high peak of new cases in China was observed. The reason why so many clinically diagnosed cases appeared was not clear.MethodsAll data of new cases in China were acquired from WHO situation reports. Linear fitting was used to infer the ability to detect COVID-19 infections. Primer-BLAST and nucleotide blast were applied to check the specificity of primers. Expression data of human mRNA in different tissues was obtained from Human Protein Atlas.FindingsBased on the data and analysis of changes of new laboratory-confirmed cases and new clinically diagnosed cases, it was inferred that there were many false-negative results in all clinically diagnosed cases in Hubei province. There were eight non-specific primers in dozens of primers used in clinical or research detection of COVID-19. Among them, a pair of primer for the ORF1ab regions of SARS-CoV-2 genome well matched some human mRNAs such as Cathepsin C transcripts. Compared to other transcripts, Cathepsin C mRNA had a high abundance in tonsil, lung and small intestine.InterpretationSome non-specific RT-PCR primers could cause the serious interference during RT-PCR amplification so as to increase the risk of false-negative diagnoses for COVID-19 infections.FundingKey Research Project of the Higher Education of Henan ProvinceResearch in contextEvidence before this studyThe author searched PubMed on April 15, 2020, for papers that describe false-negative RT-PCR detection of COVID-19 by using the search terms “COVID-19”, “false-negative” and “RT-PCR”, with no language or time restrictions. Eleven investigations only presented the rate of false-negative detection or the importance of positive chest CT finding. There were no reports referring the primer problems of false-negative detection in COVID-19 infections.Added value of this studyThe author had found that some primers could amplify the human mRNA in specimens, which mixed SARS-CoV-2 viral particles and other tissue cells. A pair of primer provided by China CDC could vastly match the sequences of human CTSC transcripts with high abundance. That could lead to false-negative results in detection of COVID-19 infections.Implications of all the available evidenceAlthough there were so many false-negative results in detection of COVID-19 infections in China, the exact reason was not clear. Problems in sampling and test condition were discussed thoroughly, but conclusions were usually contradictory. Therefore, the work could promote the verification of the false-negative detection of COVID-19 infections in China.

Pain Management Assessment Beyond the Physician Encounter

2018 ◽  
Author(s):  
Anand C. Thakur
Keyword(s):  
False Negative ◽  
Opioid Therapy ◽  
Test Results ◽  
Prescribing Practices ◽  
Negative Results ◽  
False Negative Results ◽  
Urine Drug ◽  
Monitoring Effort ◽  
Pain Patients

The long-term use of opioids in the treatment of chronic pain patients has increased dramatically over the last two decades. With this increase has come abuse, misuse, diversion, and overdose deaths, resulting in tremendous media attention. Further, there has been an increase in regulatory scrutiny of the prescribing practices of healthcare professionals. Monitoring patient compliance with chronic opioid therapy has become very important. Urine drug monitoring and patient agreements are part of this monitoring effort. However, interpreting test results can be challenging and applying these results to patient care can be complex. Metabolites, interfering substances, and false-positives and false-negative results all need to be considered when interpreting test results. Test results should not be considered sacrosanct and should always be an opportunity for discussion with a patient.

scholarly journals Impedimetric screening for bacteriuria

1978 ◽  
Vol 7 (3) ◽  
pp. 273-278
Author(s):  
P Cady ◽  
S W Dufour ◽  
P Lawless ◽  
B Nunke ◽  
S J Kraeger
Keyword(s):  
False Negative ◽  
Positive Culture ◽  
Impedance Change ◽  
Initial Concentration ◽  
Negative Results ◽  
False Negative Results ◽  
Time Required ◽  
The Cost ◽  
Positive Results ◽  
Selection Of

A rapid, automated instrumental procedure for distinguishing urine cultures containing greater than 10(5) organism per ml is described. The method is based upon the measurement of changes in impedance that take place as microorganisms alter the chemical composition of the medium. The time required to detect impedance change is inversely related to the initial concentration of microorganisms in the sample. By defining an impedance-positive culture as one that gives detectable impedance change within 2.6 h, 95.8% of 1,133 urine cultures tested were correctly classified as containing more than or fewer than 10(5) organisms per ml. Selection of a longer detection time decreases false negative results at the cost of increased false positive results. Impedance screening is compared with screening data reported in the literature using adenosine-5'-triphosphate detection, microcalorimetry, electrochemical measurements, and optical microscopy.

scholarly journals Evaluating the Cost-Effectiveness of Proposed Algorithms for C. difficile Infection in Different Pretest Probability Settings

2020 ◽  
Vol 41 (S1) ◽  
pp. s224-s225
Author(s):  
Mirian Dal Ben ◽  
Maura Oliveira ◽  
Paola Cappellano ◽  
Jorge Sampaio ◽  
Maria Beatriz Dias
Keyword(s):  
Mathematical Model ◽  
Cost Effectiveness ◽  
Positive Result ◽  
False Positive ◽  
Annual Cost ◽  
False Negative ◽  
Pretest Probability ◽  
Negative Results ◽  
False Negative Results ◽  
The Cost

Background: The use of real-time polymerase chain reaction (RT-PCR) as a first-line test for the diagnosis of Clostridioides difficile may result in overdiagnosis and overtreatment because the test is not capable of distinguishing infection from carriage. Toxin EIA assays have impeditive low sensitivity. Some algorithms using enzyme immunoassay for glutamate dehydrogenase (GDH) antigen and toxins A and B as the first step have been proposed to increase diagnostic performance. However, cost-effectiveness of different diagnostic algorithms would depend on the cost of each test and on the pretest probability in different settings. The objective of the present study was to evaluate the cost-effectiveness of 2 algorithms proposed by current guidelines to diagnose C. difficile infection by developing a mathematical model that would take into account the epidemiology and costs in our hospital. Methods: The study was conducted in a 480-bed tertiary-care teaching hospital in So Paulo, Brazil. All suspected C. difficile infection cases from January to December of 2017 were evaluated for pretest probability analysis. All stools collected from patients with a requested PCR test for suspected C. difficile infection were selected for additional testing to measure the specificity and sensitivity of each different test: C. diff GDH/Toxin A/B combined test, Toxin A/B Microplate Assay, GDH, and PCR. Toxigenic stool culture for C. difficile was considered the gold standard. A mathematical model was developed and simulations were done. The outcomes evaluated were: final annual costs with diagnostic tests in US dollars and number of patients receiving a false-positive or a false-negative diagnosis in a year simulation. Results: In total, 1,441 stool samples were tested by PCR for C. difficile in our institution from January 2017 to December 2017. Overall, 206 had a positive result, with a pretest probability of 14.3%. In our simulations, the PCR-based algorithm had an annual cost of US$279,914.25, with 4 false-negative results and 8 false-positive results. The implementation of a GDH/Toxin/PCR stepwise algorithm would have reduced the annual cost to US$160,488.75, with 6 false-negative results and 1 false-positive result. Simulations of annual cost and performance of the 2 algorithms have shown that the stepwise algorithm would still be advantageous in settings with higher pretest probabilities (Fig. 1). Conclusions: A stepwise algorithm based on GDH/Toxin before PCR seems to be more cost-effective, even in settings with higher pretest probabilities.Funding: NoneDisclosures: None

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