False-Negative Results with Levodopa for Early Detection of Huntington's Disease

The aim of this work was to investigate whether an enzyme-linked immunosorbent assay (ELISA) was useful for early detection of maedi-visna virus (MVV) infection in sheep under field conditions. An ELISA based on p25 recombinant protein and a gp46 synthetic peptide was used. Sequentially obtained serum samples ( n = 1,941) were studied for 4 years. ELISA results were compared with those of the agar gel immunodiffusion (AGID) test, and results of both tests were compared with a reference result established using consensus scores for at least 2 of 3 serologic techniques (AGID, ELISA, and western blotting, which was used to resolve result discrepancies between the other 2 techniques). A total of 247 discrepancies were observed between ELISA and AGID. Of these, 131 were due to an earlier detection of 120 sera by the ELISA and 11 sera by AGID. The remaining discrepancies (116) were due to the presence of false reactions in both tests. Fewer false-negative results were found by ELISA than with AGID (6 vs. 69 sera, respectively), whereas the number of false-positive results was virtually the same for ELISA and AGID (21 vs. 20, respectively). In relation to the reference result, ELISA sensitivity and specificity were 97.8% and 98.2%, respectively, whereas values for AGID were 76.3% and 98.3%, respectively. The agreement between ELISA and the reference result was higher than that between AGID and the reference result (κ value: 0.96 and 0.77, respectively). A variation in the ELISA signal (based on optical density) was observed during the study period, suggesting different antibody levels throughout the animal's life. The ELISA was useful for detecting MVV-infected sheep in field conditions and has potential for use in control and eradication programs.

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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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