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 ◽  
...  

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.

1999 ◽  
Vol 41 (3) ◽  
pp. 151-154 ◽  
Author(s):  
Míriam Oliveira e ROCHA ◽  
Rômulo Teixeira de MELLO ◽  
Tânia Mara Pinto Dabés GUIMARÃES ◽  
Vicente de Paulo Coelho Peixoto de TOLEDO ◽  
Maria da Conceição Carneiro Gonçalves MOREIRA ◽  
...  

It is known that fecal examination to detect Giardia lamblia cysts or trophozoites produces a high percentage of false-negative results. A commercially available immunoenzymatic assay (ProSpecT Giardia Microplate Assay, Alexon, Inc., BIOBRÁS) to detect G. lamblia specific coproantigen was evaluated for the first time in Brazil. A total of 90 specimens were tested. Each specimen was first tested as unpreserved stool, and then it was preserved in 10% Formalin to be tested 2 months later. The assay was able to identify all the 30 positive patients (sensitivity = 100.0%) by visual or spectrophotometric examination in the unpreserved specimens and was negative in 57 of the 60 patients without G. lamblia (specificity = 95.0%). The assay identified 27 of the 30 positive patients (sensitivity = 90.0%) and was negative in 59 of the 60 negatives (specificity = 98.3%) in the preserved stools according to both readings. A marked difference was observed in the optical densities in both groups, preserved and unpreserved stools, when the G. lamblia-positive specimens were compared to the negative or positive for other intestinal parasites than G. lamblia. The assay seems a good alternative for giardiasis diagnosis, especially when the fecal examination was repeatedly negative and the patient presents giardiasislike symptoms.


2019 ◽  
Vol 21 (3) ◽  
pp. 26-32
Author(s):  
Giunel S Aliyeva ◽  
Galina P Korzhenkova ◽  
Irina V Kolyadina

Clinicoroentgenological diagnosis of early breast cancer - BC (non-invasive or invasive small-sized cancers) is difficult due to the absence of any characteristic clinical symptoms and pathognomonic roentgenological signs of the malignant process. Screening of BC has shown to be one of the most successful projects for early diagnosis of malignancies, but the probability to receive false negative results using screening mammography reaches 12%, and, on the one hand, this is due to interval cancers, and on the other hand - to defects in the primary screening. Among the factors associated with the likelihood of ineffective screening of BC, the most authors highlight such as high breast density, preceding the breast biopsy for a benign process, young age, as well as the use of hormone replacement therapy. The main methods of instrumental BC diagnostics are mammography, ultrasound (US), magnetic resonance imaging (MRI) and positron emission tomography (PET). Mammography is the "gold standard" for both screening and best diagnostics, but is characterized by a high proportion of both false positive and false negative results, and this can be partially solved by the use of digital mammography with tomosynthesis (performing a series of mammography images obtained at different angles and producing the focused 3-D images). Contrast enhanced mammography allows to identify angiogenesis in the area of the predicted malignancy, but is characterized by a high radiation exposure. Breast ultrasound is characterized by low specificity of the method and the high dependence of the result of data interpretation depending on physician qualifications. MRI of the breast for screening is characterized by high sensitivity, but also high cost and high proportion of false positive results. The role of PET/computer tomography in the diagnosis of early BC remains unclear, and the informative value of research in patients with nonpalpable tumors is extremely low. The roentgenological picture of early BC is widely variable; characteristic features include the presence of clustered calcifications, lumps with jagged edges, rough multinodular lumps. However, in a significant proportion of women the only manifestation of early BC is the presence of microcalcinates. Careful analysis of the localization and the shape of microcalcinates and basic characteristics allows correctly interpret the roentgenological diagnosis and helps to choose the optimal diagnostic and treatment algorithm.


2020 ◽  
Author(s):  
Chi Gao ◽  
Kaiyuan Zhang ◽  
Qinghe Wang ◽  
Ling Zhao ◽  
Rong Chen ◽  
...  

Abstract A fluorescent visual identification system of Paris polyphylla var. yunnanensis was established based on internal transcribed spacer barcoding. It is proposed for the first time that P. polyphylla var. yunnanensis should be divided into two types of genotypes: YN-I and YN-II according to single nucleotide polymorphism of internal transcribed spacer. In order to avoid false-negative results, two pairs of specific primers for YN-I and YN-II were designed, respectively, and specific visual fluorescent identification systems was established by SYBR Green I fluorescent dye was directly introduced into the PCR system which can be observed directly with the naked eye for the green fluorescent color of PCR system. Therefrom, it has realized the rapid and directly visual identification of two genotypes of P. polyphylla var. yunnanensis from its common nine adulterants. This study proposed for the first time the existence of different genotypes on the legal basis of Rhizoma Paridis, and provided a model for the accurate identification of different genotypes.


2016 ◽  
Vol 54 (6) ◽  
pp. 1650-1652 ◽  
Author(s):  
Martin C. W. Chan ◽  
Kirsty Kwok ◽  
Tin-Nok Hung ◽  
Paul K. S. Chan

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.


Foods ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2041
Author(s):  
Yingying Li ◽  
Haihuan Xie ◽  
Jin Wang ◽  
Xiangmei Li ◽  
Zhili Xiao ◽  
...  

In recent years, furosemide has been found to be abused in slimming health foods. There is an urgent need for a simpler, faster method for detecting furosemide in slimming health foods. In this study, a rapid, convenient and sensitive lateral flow immunochromatography (LFIA) based on Au nanoparticles (AuNPs) was established for the first time. Under optimal conditions, the qualitative limit of detection (LOD) of the AuNPs-based LFIA was 1.0~1.2 μg/g in slimming health foods with different substrates. AuNPs-LFIA could specifically detect furosemide within 12 min (including sample pretreatment) and be read by the naked eye. The developed AuNPs-LFIA showed high consistency with liquid chromatography with tandem mass spectrometry (LC-MS/MS), and no false positive or false negative results were found in spiked slimming health foods, proving that the AuNPs-LFIA should be accurate and reliable. The AuNPs-LFIA reported here provides a serviceable analytical tool for the on-site detection and rapid initial screening of furosemide for the first time.


2020 ◽  
Author(s):  
Chi Gao ◽  
Kaiyuan Zhang ◽  
Qinghe Wang ◽  
Ling Zhao ◽  
Rong Chen ◽  
...  

Abstract A fluorescent visual identification system of Paris polyphylla var. yunnanensis was established based on internal transcribed spacer barcoding. It is proposed for the first time that P. polyphylla var. yunnanensis should be divided into two types of genotypes: YN-I and YN-II according to single nucleotide polymorphism of internal transcribed spacer. In order to avoid false-negative results, two pairs of specific primers for YN-I and YN-II were designed, respectively, and specific visual fluorescent identification systems was established by SYBR Green I fluorescent dye was directly introduced into the PCR system which can be observed directly with the naked eye for the green fluorescent color of PCR system. Therefrom, it has realized the rapid and directly visual identification of two genotypes of P. polyphylla var. yunnanensis from its common nine adulterants. This study proposed for the first time the existence of different genotypes on the legal basis of Rhizoma Paridis, and provided a model for the accurate identification of different genotypes.


1974 ◽  
Vol 31 (02) ◽  
pp. 273-278
Author(s):  
Kenneth K Wu ◽  
John C Hoak ◽  
Robert W Barnes ◽  
Stuart L Frankel

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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