Enzyme Activity for Determination of Presence of Fabry Disease in Women Results in 40% False-Negative Results

Background: A lifelong strict gluten-free diet is the only available treatment for celiac disease, but total exclusion of gluten is difficult to achieve. The aim of this study was to determine the range of time and the amount of gluten immunogenic peptides (GIP) excreted in urine after specific gluten ingestions. Methods: 20 healthy participants followed the same diet for 12 days in which 50 mg and 2 g of gluten were ingested and all the urinations were collected. GIP were analyzed by lateral flow immunoassay (LFIA) tests and quantified using an LFIA reader. Results: GIP were detected in 15% and 95% of participants after 50 mg and 2 g gluten intakes, respectively. The higher frequency and concentration of GIP was found between 6 and 9 h after both gluten ingestions. The ranges of detection were 3–12 h (50 mg) and 0–15 h (2 g). Conclusions: An increase in the frequency of urine tests may be a suitable approach to avoid false negative results. The use of the LFIA test in three urine samples collected at different times may show a sensitivity of 19.6% for a gluten ingestion like 50 mg, increasing to 93% after 2 g consumption.

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68GA-PSMA — LABELED BIOMARKER FOR POSITRON EMISSION TOMOGRAPHY (LITERATURE REVIEW)

Translational Medicine ◽

10.18705/2311-4495-2018-5-5-46-52 ◽

2018 ◽

Vol 5 (5) ◽

pp. 46-52

Author(s):

M. D. Poyda ◽

D. V. Ryzhkova ◽

A. A. Stanzhevsky

Keyword(s):

False Negative ◽

Malignant Neoplasms ◽

Diagnostic Efficiency ◽

Negative Results ◽

Tumor Focus ◽

Positron Emission ◽

False Negative Results ◽

Pet Ct ◽

Risk Patients

The review is devoted to the analysis of the diagnostic efficiency of combined positron emission and computed tomography (PET / CT) with the radiopharmaceutical 68Ga-PSMA in the initial staging of prostate cancer in middle- and high-risk patients, the determination of the tumor focus in the biochemical recurrence of the disease, and monitoring the effectiveness of systemic and radionuclide therapy. The causes of false positive and false negative results of PET / CT are listed and indications for the procedure are presented as well. 68Ga-PSMA diagnostic possibilities as a labeled biomarker of neovascularization in malignant neoplasms of other localizations are briefly described.

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Determination of Bacterial Endotoxins in Drugs: False-Negative Results

Pharmaceutical Chemistry Journal ◽

10.1007/s11094-018-1751-3 ◽

2018 ◽

Vol 51 (12) ◽

pp. 1119-1122

Author(s):

O. V. Shapovalova ◽

N. P. Neugodova ◽

G. A. Sapozhnikova ◽

L. V. Simutenko ◽

A. A. Agashirinova

Keyword(s):

False Negative ◽

Negative Results ◽

Bacterial Endotoxins ◽

False Negative Results

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Does a change in quality control results influence the sensitivity of an anti-HCV test?

Clinical Chemistry and Laboratory Medicine (CCLM) ◽

10.1515/cclm-2020-0031 ◽

2020 ◽

Vol 58 (8) ◽

pp. 1372-1380 ◽

Cited By ~ 1

Author(s):

Wayne J. Dimech ◽

Giuseppe A. Vincini ◽

Liza M. Cabuang ◽

Megan Wieringa

Keyword(s):

Quality Control ◽

False Negative ◽

External Quality Assessment Scheme ◽

Clinical Sensitivity ◽

Root Cause ◽

Negative Results ◽

False Negative Results ◽

Three Samples ◽

The Difference

AbstractBackgroundLaboratories use quality control (QC) testing to monitor the extent of normal variation. Assay lot number changes contribute the greatest amount of variation in infectious disease serology testing. An unexpected change in six lots of an anti-HCV assay allowed the determination of the effect these lot changes made to the assay’s clinical sensitivity.MethodsTwo sets of seroconversion samples comprising of 44 individual samples and 9 external quality assessment scheme (EQAS) samples, all positive to anti-HCV, were tested in affected and unaffected assay lots, and the difference in the quantitative and qualitative results of the samples was analyzed.ResultsOf 44 low-positive seroconversion samples tested in affected and unaffected assay lots, only three samples had results reported below the assay cutoff when tested on two of the six affected assay lot. A further sample had results below the cutoff for only one affected lot. None of the EQAS samples reported false-negative results. Samples having a signal to cutoff value of less than 6.0 generally had lower results in the affected lots compared with the unaffected lots.ConclusionsUnexpected changes in QC reactivity related to variation, in particular assay lot changes, may affect patient results. This study demonstrated that QConnect Limits facilitated the detection of an unexpectedly large variation in QC test results, allowed for the identification of the root cause of the change, and showed that the risk associated with the change was low but credible. The use of evidence-based QC program is essential to detect changes in test systems.

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Detection of microsatellite instability in a panel of solid tumours with the Idylla MSI Test using extracted DNA

Journal of Clinical Pathology ◽

10.1136/jclinpath-2020-206581 ◽

2020 ◽

Vol 74 (1) ◽

pp. 36-42 ◽

Cited By ~ 1

Author(s):

Adrien Pécriaux ◽

Loetitia Favre ◽

Julien Calderaro ◽

Cécile Charpy ◽

Jonathan Derman ◽

...

Keyword(s):

Limit Of Detection ◽

False Negative ◽

Solid Tumours ◽

Automated System ◽

Ovarian Carcinomas ◽

Negative Results ◽

False Negative Results ◽

Large Panel ◽

Msi Analysis

AimDuring the last few years, determination of microstatellite instability (MSI) status has become a routine part of clinical practice, essentially to detect Lynch syndrome. Recently, MSI testing has increased with the development of immunotherapy and has expanded to a large panel of solid tumours. The aim of our work was to evaluate a fully automated system developed by Biocartis, the Idylla MSI Test, which performs an MSI analysis within 150 min.MethodsA comparison between pentaplex PCR, immunohistochemistry and Idylla MSI Test was performed in 53 colorectal carcinoma samples, 7 small intestine adenocarcinomas, 15 duodenal and pancreatic adenocarcinomas, 16 gastric tumours, 15 endometrial adenocarcinomas, 5 ovarian carcinomas and 4 cases of urinary tract tumours using extracted DNA. Limit-of-detection (LOD) experiment was also done using a commercial DNA known to harbour MSI phenotype.ResultsThe overall sensitivity was 94% and the overall specificity was 100%. Two invalid and three false-negative results were observed. Our experiments showed that the amount of DNA loaded into the cartridge was decisive and should be superior to 25 ng. LOD comprised between 4% and 8%.ConclusionOverall, we have demonstrated that the Idylla MSI Test is a rapid and valid option to detect MSI phenotype which can be used in a large panel of solid tumours.

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Application of the AhR reporter gene assay for the determination of PCDD/Fs and DL-PCBs in feed samples

Journal of Veterinary Research ◽

10.1515/jvetres-2017-0066 ◽

2017 ◽

Vol 61 (4) ◽

pp. 473-481 ◽

Cited By ~ 1

Author(s):

Jadwiga Piskorska-Pliszczyńska ◽

Paweł Małagocki ◽

Beata Furga ◽

Magdalena Gembal ◽

Joanna Cebulska

Keyword(s):

Reporter Gene ◽

False Negative ◽

Screening Method ◽

Minimal Risk ◽

Negative Results ◽

False Negative Results ◽

Feed Control ◽

Gene Assay

AbstractIntroduction: Polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (DL-PCBs) belong to a well-known group of pollutants. Present in feedstuffs, they bioaccumulate in tissues of food-producing animals. Food is the source of over 90% of human PCDD/Fs and DL-PCBs intake. Thus, feed control is one of the pillars of the EU strategy and a mean of reducing human exposure. The article presents AhR based reporter gene bioassay method for PCDD/Fs and DL-PCBs analysis in feed and its validation results.Material and Methods: Analytes were extracted from samples with fat. Subsequently, fat and other interferences were removed from extract using sulphuric acid modified silica. Extract was further cleaned and PCDD/Fs separated from DL-PCBs using carbon column. Contaminants detection was performed using H1L6.1c3 cell line, which produces luciferase in response to AhR ligands present in extract.Results: Performance characteristics (repeatability, reproducibility, and apparent recovery) fulfil the requirements of Regulation 2017/771/EU. The positive correlation between bioassay and reference HRGC-HRMS method was confirmed. Moreover, the role of screening method used in connection with the confirmatory HRGC-HRMS method in providing feed and food safety has been discussed.Conclusion: Bioassay is a useful method for dioxin and DL-PCBs analysis, allowing cost reduction of monitoring programmes with minimal risk of false negative results.

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Clinical Use of Capillary PCR To DiagnoseMycoplasma Pneumonia

Journal of Clinical Microbiology ◽

10.1128/jcm.38.4.1382-1384.2000 ◽

2000 ◽

Vol 38 (4) ◽

pp. 1382-1384 ◽

Cited By ~ 26

Author(s):

Junichi Honda ◽

Takafumi Yano ◽

Mikako Kusaba ◽

Junko Yonemitsu ◽

Hiromoto Kitajima ◽

...

Keyword(s):

Throat Swab ◽

False Negative ◽

Community Acquired Pneumonia ◽

Pcr Analysis ◽

Negative Results ◽

Specimen Collection ◽

False Negative Results ◽

Positive Results ◽

Patient Burden

In the present study, serologic data were compared with data obtained by capillary PCR to establish the efficacy of capillary PCR for the determination of Mycoplasma infection in samples obtained from throat swabs, bronchoalveolar lavage fluids (BALF), and sputum of patients with Mycoplasma pneumonia. We performed PCR analysis for Mycoplasma DNA on a total of 325 samples from 197 patients with community-acquired pneumonia and in whom Mycoplasma pneumonia was suspected. There were 68 PCR-positive specimens. Review of the differences in PCR positivity rates based on the site of specimen collection showed the highest rate of detection (28.6%) from throat swabs. From among the 31 patients with significantly elevated titers of serum Mycoplasmaantibodies, the PCR results were positive for 25 patients. Thus, capillary PCR had a sensitivity of 80.6% (25 of 31). Five of the six false-negative results were from throat swab specimens. Moreover, testing (PCR) had been performed only once for these five patients with false-negative results. From among the PCR-positive findings from BALF specimens, there were no false-positive results. BALF specimens were very useful, except for the technical procedures and increased patient burden required to obtain these specimens. We suggest that the use of throat swab specimens in capillary PCR is much more suitable for diagnosing Mycoplasma pneumonia in routine clinical practice; however, careful throat swab specimen collection and an increase in the number of times that the PCR is performed are necessary to reduce the rate of false-negative results.

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