Implementation of theBacillus cereusmicrobiological plate used for the screening of tetracyclines in raw milk samples with STAR protocol – the problem with false-negative results solved

SummaryA rapid fluorogenic medium was evaluated for the detection ofEscherichia coliin dairy products. The medium was capable of detectingEsch. coliafter 7·5 h incubation at 41·5 °C. Samples of pasteurized milk (136), raw milk (63), soft cheese (60) and pasteurized cream (39) were examined with media based on 4-methylumbelliferyl-β-D-glucuronide (MUG-7) and Violet red bile agar and there were no significant differences between the numbers ofEsch. colidetected on the two media. MUG-7 medium had a specificity of 98·6% and the small number of organisms giving a false positive reaction were identified asKlebsiella pneumoniae. The incidence of false negative results was ∼2%. MUG-7 medium was suitable for pour plate, spread plate and membrane filtration methods. Possible applications of the method are discussed.

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PCR Assay With Host Specific Internal Control for Staphylococcus Aureus From Bovine Milk Samples

Macedonian Veterinary Review ◽

10.14432/j.macvetrev.2015.01.038 ◽

2015 ◽

Vol 38 (1) ◽

pp. 97-100 ◽

Cited By ~ 1

Author(s):

Zafer Cantekin ◽

Yasar Ergun ◽

Hasan Solmaz ◽

Gamze Özge Özmen ◽

Melek Demir ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Polymerase Chain Reaction ◽

False Negative ◽

Bovine Milk ◽

Chain Reaction ◽

Specific Primers ◽

Milk Samples ◽

Negative Results ◽

False Negative Results ◽

Polymerase Chain

Abstract Staphylococcus aureus is considered as one of the most important and common pathogens of bovine mastitis. Polymerase Chain Reaction is frequently proposed in the diagnosis of S. aureus directly from milk samples instead of classical culture. However, false-negative results may occur in the polymerase chain reaction analysis performed directly from clinical material. For the purpose of disclosing the false negative results, the use of internal amplification controls can be beneficial. Therefore, in this study a new polymerase chain reaction technique with host specific internal amplification control was developed by optimizing S. aureus-specific primers in combination with bovine specific primers. The effectiveness of the developed technique in this study was attempted in milk samples from bovine subclinical mastitis. This technique has the potential to detect S. aureus from bovine milk samples or dairy products.

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The nitroblue tetrazolium test. An evaluation of the false-positive and false-negative results

Archives of Internal Medicine ◽

10.1001/archinte.133.3.432 ◽

1974 ◽

Vol 133 (3) ◽

pp. 432-436 ◽

Cited By ~ 1

Author(s):

M. E. Campos

Keyword(s):

False Positive ◽

False Negative ◽

Nitroblue Tetrazolium ◽

Negative Results ◽

False Negative Results ◽

Nitroblue Tetrazolium Test ◽

Tetrazolium Test

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False negative results of real time strain elastography in thyroid nodular disease

Ultraschall in der Medizin - European Journal of Ultrasound ◽

10.1055/s-0036-1587848 ◽

2016 ◽

Vol 37 (S 01) ◽

Author(s):

D Stoian ◽

M Craciunescu ◽

M Craina ◽

S Pantea ◽

F Varcus

Keyword(s):

Real Time ◽

False Negative ◽

Strain Elastography ◽

Negative Results ◽

False Negative Results

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

Thrombosis and Haemostasis ◽

10.1055/s-0038-1649161 ◽

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.

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Scoring System for the Diagnosis of COVID-19

The Open Public Health Journal ◽

10.2174/1874944502013010413 ◽

2020 ◽

Vol 13 (1) ◽

pp. 413-414 ◽

Cited By ~ 1

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.

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

Anti-Infective Agents ◽

10.2174/2211352518999200629165108 ◽

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).

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

Coronaviruses ◽

10.2174/2666796701999201209142919 ◽

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.

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

Aesthetic Surgery Journal ◽

10.1093/asj/sjab194 ◽

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.

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

Viruses ◽

10.3390/v13050730 ◽

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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