scholarly journals Reduced Diagnostic Performance of Two Norovirus Antigen Enzyme Immunoassays for the Emergent Genogroup II Genotype 17 Kawasaki 2014 Variant

2016 ◽  
Vol 54 (6) ◽  
pp. 1650-1652 ◽  
Author(s):  
Martin C. W. Chan ◽  
Kirsty Kwok ◽  
Tin-Nok Hung ◽  
Paul K. S. Chan
Keyword(s):  
Infection Control ◽  
Diagnostic Performance ◽  
Patient Management ◽  
False Negative ◽  
Enzyme Immunoassays ◽  
Negative Results ◽  
False Negative Results

Two commonly used norovirus enzyme immunoassays have reduced diagnostic performance, with clinical sensitivities ranging from 11% to 35% for the detection of the recently emerging genogroup II genotype 17 (GII.17) Kawasaki 2014 variant that caused the majority of infections in Asia during the winter of 2014 to 2015. False-negative results can compromise infection control and patient management.

scholarly journals Importance of Adequate qPCR Controls in Infection Control

Diagnostics ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2373
Author(s):  
Matthew Oughton ◽  
Ivan Brukner ◽  
Shaun Eintracht ◽  
Andreas I. Papadakis ◽  
Alan Spatz ◽  
...  
Keyword(s):  
Infection Control ◽  
False Negative ◽  
Significant Proportion ◽  
Control Measures ◽  
Negative Results ◽  
Minimal Sample ◽  
Infection Control Measures ◽  
False Negative Results ◽  
Quantitative Sample ◽  
First Time

Respiratory screening assays lacking Sample Adequacy Controls (SAC) may result in inadequate sample quality and thus false negative results. The non-adequate samples might represent a significant proportion of the total performed tests, thus resulting in sub-optimal infection control measures with implications that may be critical during pandemic times. The quantitative sample adequacy threshold can be established empirically, measuring the change in the frequency of positive results, as a function of the numerical value of “sample adequacy”. Establishing a quantitative threshold for SAC requires a big number/volume of tests to be analyzed in order to have a statistically valid result. Herein, we are offering for the first time clear clinical evidence that a subset of results, which did not pass minimal sample adequacy criteria, have a significantly lower frequency of positivity compared with the “adequate” samples. Flagging these results and/or re-sampling them is a mitigation strategy, which can dramatically improve infection control measures.

scholarly journals Immunoassay-Based Drug Tests Are Inadequately Sensitive for Medication Compliance Monitoring in Patients Treated for Chronic Pain

10.36076/se9 ◽  
2017 ◽  
Vol 2 (20;2) ◽  
pp. sE1-sE9 ◽  
Author(s):  
Stacy Melanson
Keyword(s):  
Mass Spectrometry ◽  
Chronic Pain ◽  
Pain Management ◽  
Drug Use ◽  
Illicit Drugs ◽  
False Negative ◽  
The United States ◽  
Enzyme Immunoassays ◽  
Negative Results ◽  
False Negative Results

Background: Enzyme immunoassays (EIA) have notable limitations for monitoring therapeutic compliance in pain management. Chromatography coupled with mass spectrometry provides definitive results and superior sensitivity and specificity over traditional EIA testing. Objective: To analyze and compare the sensitivity of EIA results together with known prescriptions to liquid chromatography-tandem mass spectrometry (LC-MS/MS) for monitoring drug use (and abuse) in patients treated for chronic pain. Study Design: A total of 530 urine samples from patients being treated for chronic pain were studied. Setting: Pain management clinic in the United States. Methods: The samples were tested for a profile of chronic pain medications and illicit drugs with commercially available EIA kits followed by analysis with Agilent LC-MS/MS system. Results: The EIAs exhibited poor sensitivity and high rates of false negative results in the pain management setting. For example, 21% of EIA for opiates show false negative results. Mass spectrometry methods were more sensitive, detected a broader range of drugs and metabolites, and could detect non-prescribed drug use and simulations in compliance. Limitations: Patients do not always accurately report drug use information, and some drugs do not have EIA methods available for comparative purposes. Conclusions: Mass spectrometry is a more robust and reliable method for detection of drugs used in the pain management setting. Due to the extent of undisclosed use and abuse of medications and illicit drugs, LC-MS/MS testing is necessary for adequate and accurate drug detection. In addition, LC-MS/MS methods are superior in terms of sensitivity and number of compounds that can be screened, making this a better method for use in pain management. Key words: Pain management, enzyme immunoassays, mass spectrometry, urine drug testing, prescription status, compliance

Critical Evaluation of Impedance Phlebography for the Diagnosis of Deep Vein Thrombosis

1974 ◽  
Vol 31 (02) ◽  
pp. 273-278
Author(s):  
Kenneth K Wu ◽  
John C Hoak ◽  
Robert W Barnes ◽  
Stuart L Frankel
Keyword(s):  
Deep Vein Thrombosis ◽  
False Positive ◽  
False Negative ◽  
Critical Evaluation ◽  
Original Method ◽  
Vein Thrombosis ◽  
Negative Results ◽  
False Negative Results ◽  
Deep Vein ◽  
Positive Results

SummaryIn order to evaluate its daily variability and reliability, impedance phlebography was performed daily or on alternate days on 61 patients with deep vein thrombosis, of whom 47 also had 125I-fibrinogen uptake tests and 22 had radiographic venography. The results showed that impedance phlebography was highly variable and poorly reliable. False positive results were noted in 8 limbs (18%) and false negative results in 3 limbs (7%). Despite its being simple, rapid and noninvasive, its clinical usefulness is doubtful when performed according to the original method.

Scoring System for the Diagnosis of COVID-19

2020 ◽  
Vol 13 (1) ◽  
pp. 413-414 ◽  
Author(s):  
Mohamed Farouk Allam
Keyword(s):  
Scoring System ◽  
Clinical Symptoms ◽  
False Negative ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Pcr Assay ◽  
Negative Results ◽  
False Negative Results ◽  
Symptoms And Signs

Due to the international spread of COVID-19, the difficulty of collecting nasopharyngeal swab specimen from all suspected patients, the costs of RT-PCR and CT, and the false negative results of RT-PCR assay in 41% of COVID-19 patients, a scoring system is needed to classify the suspected patients in order to determine the need for follow-up, home isolation, quarantine or the conduction of further investigations. A scoring system is proposed as a diagnostic tool for suspected patients. It includes Epidemiological Evidence of Exposure, Clinical Symptoms and Signs, and Investigations (if available). This scoring system is simple, could be calculated in a few minutes, and incorporates the main possible data/findings of any patient.

Detection of Streptococcus pneumoniae in Sputum Samples by Real- Time PCR.

2020 ◽  
Vol 18 ◽  
Author(s):  
Pegah Shakib ◽  
Mohammad Reza Zolfaghari
Keyword(s):  
Streptococcus Pneumoniae ◽  
Real Time ◽  
Real Time Pcr ◽  
False Negative ◽  
Cross Sectional Study ◽  
Laboratory Culture ◽  
Cross Sectional ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Method

Background: Conventional laboratory culture-based methods for diagnosis of Streptococcus pneumoniae are time-consuming and yield false negative results. Molecular methods including real-time (RT)-PCR rapid methods and conventional PCR due to higher sensitivity and accuracy have been replaced instead traditional culture assay. The aim of the current study was to evaluate lytA gene for detection of Streptococcus pneumoniae in the cerebrospinal fluid of human patients with meningitis using real-time PCR assay. Material and Methods: In this cross-sectional study, a total of 30 clinical specimens were collected from patients in a period from September to December 2018. In order to evaluate the presence of lytA gene, conventional and real-time PCR methods were used without culture. Results: From 30 sputum samples five (16.66%) isolates were identified as S. pneumoniae by lytA PCR and sequencing. Discussion: In this research, an accurate and rapid real-time PCR method was used, which is based on lytA gene for diagnosis of bacteria so that it can be diagnosed. Based on the sequencing results, the sensitivity for detection of lytA gene was 100% (5/5).

COVID-19: how nuclear medicine can provide a differential diagnosis in very dubious case

Coronaviruses ◽  
2020 ◽  
Vol 01 ◽  
Author(s):  
Maria Silvia De Feo ◽  
Viviana Frantellizzi ◽  
Giuseppe De Vincentis
Keyword(s):  
Infectious Disease ◽  
Differential Diagnosis ◽  
Ct Scan ◽  
Imaging Technique ◽  
False Negative ◽  
Clinical Signs ◽  
Negative Results ◽  
Infectious Disease Department ◽  
False Negative Results ◽  
99Mtc Hmpao

Background: We present the case of a 55-year-old woman, admitted to the Infectious Disease Department of Policlinico Umberto I, Rome, in mid-March 2020, with suspicion of COVID-19 infection. Objective: The rRT-PCR was negative and the following CT scan, performed to exclude false-negative results and help diagnosis, was inconclusive. Methods: It was decided to submit the patient to 99mTc-HMPAO-labelled leukocyte scan. Results: This exam led to the diagnosis of infective endocarditis. Conclusion: In the present pandemic scenario, 99mTc-HMPAO-labelled leukocyte scan represents a reliable imaging technique for differential diagnosis with COVID-19 in patients with confusing clinical signs, possible false-negative rRT-PCR results and inconclusive CT scan.

Aspiration Revisited: Prospective Evaluation of a Physiologically Pressurized Model With Animal Correlation and Broader Applicability to Filler Complications

2021 ◽  
Author(s):  
Hyoung-Jin Moon ◽  
Won Lee ◽  
Ji-Soo Kim ◽  
Eun-Jung Yang ◽  
Hema Sundaram
Keyword(s):  
Normal Saline ◽  
False Negative ◽  
Vascular Complications ◽  
Filler Injection ◽  
Negative Results ◽  
Needle Position ◽  
False Negative Results ◽  
In Vivo Testing

Abstract Background Aspiration testing before filler injection is controversial. Some believe that aspiration can help prevent inadvertent intravascular injection, while others cite false-negative results and question its value given that the needle position always changes somewhat during injection procedures. Objectives To test the relation of false-negative results to the viscosity of the material within the needle lumen and determine whether a less viscous material within the needle lumen could decrease the incidence of false-negative results. Methods In vitro aspiration tests were performed using 30-G and 27-G needle gauges, two cross-linked hyaluronic acid fillers, normal saline bags pressurized at 140 and 10 mmHg to mimic human arterial and venous pressures, and three needle lumen conditions (normal saline, air, and filler). Testing was repeated three times under each study condition (72 tests in total). For in vivo correlation, aspiration tests were performed on femoral arteries and central auricular veins in three rabbits (4–5 aspirations per site, 48 tests in total). Results In vitro and in vivo testing using 30-G needles containing filler both showed false-negative results on aspiration testing. In vitro and in vivo testing using needles containing saline or air showed positive findings. Conclusions False-negative results from aspiration testing may be reduced by pre-filling the needle lumen with saline rather than a filler. The pressurized system may help overcome challenges of animal models with intravascular pressures significantly different from those of humans. The adaptability of this system to mimic various vessel pressures may facilitate physiologically relevant studies of vascular complications.

scholarly journals Superiority of MALDI-TOF Mass Spectrometry over Real-Time PCR for SARS-CoV-2 RNA Detection

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 730
Author(s):  
Magda Rybicka ◽  
Ewa Miłosz ◽  
Krzysztof Piotr Bielawski
Keyword(s):  
Mass Spectrometry ◽  
Gold Standard ◽  
Viral Genome ◽  
False Negative ◽  
Rt Pcr ◽  
Rna Detection ◽  
Maldi Tof ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Test

At present, the RT-PCR test remains the gold standard for early diagnosis of SARS-CoV-2. Nevertheless, there is growing evidence demonstrating that this technique may generate false-negative results. Here, we aimed to compare the new mass spectrometry-based assay MassARRAY® SARS-CoV-2 Panel with the RT-PCR diagnostic test approved for clinical use. The study group consisted of 168 suspected patients with symptoms of a respiratory infection. After simultaneous analysis by RT-PCR and mass spectrometry methods, we obtained discordant results for 17 samples (10.12%). Within fifteen samples officially reported as presumptive positive, 13 were positive according to the MS-based assay. Moreover, four samples reported by the officially approved RT-PCR as negative were positive in at least one MS assay. We have successfully demonstrated superior sensitivity of the MS-based assay in SARS-CoV-2 detection, showing that MALDI-TOF MS seems to be ideal for the detection as well as discrimination of mutations within the viral genome.

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