scholarly journals The Reliability of a Novel Automated System for ANA Immunofluorescence Analysis in Daily Clinical Practice

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Mohammed Alsuwaidi ◽  
Margit Dollinger ◽  
Martin Fleck ◽  
Boris Ehrenstein
Keyword(s):  
Clinical Practice ◽  
Clinical Care ◽  
Daily Clinical Practice ◽  
Automated System ◽  
Visual Interpretation ◽  
Serum Samples ◽  
Negative Results ◽  
Automated Interpretation ◽  
Reading System ◽  
Positive Results

Automated interpretation (AI) systems for antinuclear antibody (ANA) analysis have been introduced based on assessment of indirect immunofluorescence (IIF) patterns. The diagnostic performance of a novel automated IIF reading system was compared with visual interpretation (VI) of IIF in daily clinical practice to evaluate the reduction of workload. ANA-IIF tests of consecutive serum samples from patients with suspected connective tissue disease were carried out using HEp-2 cells according to routine clinical care. AI was performed using a visual analyser (Zenit G-Sight, Menarini, Germany). Agreement rates between ANA results by AI and VI were calculated. Of the 336 samples investigated, VI yielded 205 (61%) negative, 42 (13%) ambiguous, and 89 (26%) positive results, whereas 82 (24%) were determined to be negative, 176 (52%) ambiguous, and 78 (24%) positive by AI. AI displayed a diagnostic accuracy of 175/336 samples (52%) with a kappa coefficient of 0.34 compared to VI being the gold standard. Solely relying on AI, with VI only performed for all ambiguous samples by AI, would have missed 1 of 89 (1%) positive results by VI and misclassified 2 of 205 (1%) negative results by VI as positive. The use of AI in daily clinical practice resulted only in a moderate reduction of the VI workload (82 of 336 samples: 24%).

scholarly journals Potential Impact of Different Cytomegalovirus (CMV) IgM Assays on an Algorithm Requiring IgM Reactivity as a Criterion for Measuring CMV IgG Avidity

2014 ◽  
Vol 21 (6) ◽  
pp. 813-816 ◽  
Author(s):  
Harry E. Prince ◽  
Mary Lapé-Nixon ◽  
Andrew Brenner ◽  
Nancy Pitstick ◽  
Marc Roger Couturier
Keyword(s):  
Cmv Infection ◽  
Serum Samples ◽  
Immunofluorescent Assay ◽  
Negative Results ◽  
Igg Avidity ◽  
Positive Serum ◽  
Chemiluminescent Immunoassay ◽  
Potential Impact ◽  
The Impact ◽  
Positive Results

ABSTRACTThe measurement of cytomegalovirus (CMV) IgG avidity is a powerful tool for identifying individuals with recent CMV infection. Because such patients are expected to be positive for CMV IgM, several investigators have suggested that CMV IgG-positive sera first be screened for CMV IgM and then only the IgM-reactive sera be tested for avidity. We investigated the impact of different CMV IgM assays on such a reflexing algorithm using a panel of 369 consecutive IgG-positive serum samples submitted for avidity testing. A bead-based immunofluorescent assay (BIFA) identified 105 IgM-positive serum samples, whereas an IgM-capture enzyme immunoassay (EIA) identified 48 IgM-positive serum samples; this marked difference led us to evaluate additional CMV IgM assays. An enzyme-linked immunofluorescent assay (ELFA) and a chemiluminescent immunoassay (CIA) were used to test all sera with discordant BIFA/EIA results, all sera with concordant positive results, and selected sera with concordant negative results. The findings indicated that the ELFA would identify 74 CMV IgM-positive samples and the CIA would identify 64. Of the 23 low-avidity serum samples, 2 were IgM negative by BIFA, 3 by ELFA and CIA, and 4 by EIA; of the 23 intermediate-avidity serum samples, 6 were IgM negative by BIFA, 10 by ELFA, and 15 by EIA and CIA. In both these avidity groups, BIFA IgM-negative sera were also negative by the other 3 assays. These findings demonstrate that an algorithm requiring CMV IgM reactivity as a criterion for CMV IgG avidity testing does not identify all low-avidity sera and thus misses some cases of acute CMV infection.

scholarly journals Evaluation of 2-column agglutination versus conventional tube technique for antibody screening

2021 ◽  
Vol 9 (3) ◽  
pp. 407-412
Author(s):  
A. Abou Jabal ◽  
T. Shubeilat ◽  
F. Hajjiri
Keyword(s):  
Serum Samples ◽  
Antibody Screening ◽  
Negative Results ◽  
Specificity And Sensitivity ◽  
Low Concentrations ◽  
Indirect Antiglobulin Test ◽  
Antiglobulin Test ◽  
Screening And Identification ◽  
Clinically Significant ◽  
Positive Results

The study aimed to determine the specificity and sensitivity of the Ortho BioVue two-column agglutination system for the detection of low concentrations of clinically significant antibodies in serum. The BioVue system was compared with the conventional tube technique [LISS-Coombs indirect antiglobulin test], and the two-stage Papenzyme test was used to resolve discrepancies between the two methods. We tested 3000 serum samples from randomly selected patients at King Hussein Medical Centre. Both the antibody screening and identification gave negative results in 2952 patients and positive results in 48 patients. We found the BioVue system to be the more sensitive technique. However, if papain enzyme-treated cells were included in the conventional tube technique when applied to antibody screening and identification, both methods would be of comparable sensitivity

scholarly journals Usefulness of real-time PCR assay targeting lipL32 gene for diagnosis of human leptospirosis in Uruguay

2013 ◽  
Vol 7 (12) ◽  
pp. 941-945 ◽  
Author(s):  
Sabina González ◽  
Juan Pablo Geymonat ◽  
Elba Hernández ◽  
Juan Martín Marqués ◽  
Felipe Schelotto ◽  
...  
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Dna Amplification ◽  
Diagnostic Sensitivity ◽  
Analytical Sensitivity ◽  
Serum Samples ◽  
Initial Management ◽  
Negative Results ◽  
Acute Infections ◽  
Positive Results

Introduction: Assays based on DNA amplification can provide information that contributes to the initial management of patients with leptospirosis. However, these have not been adopted in Uruguay. Our aim was to evaluate the performance of the lipL32 real-time PCR (qPCR) for diagnosis of leptospirosis. Methodology: We analyzed by microscopic agglutination test (MAT) and lipL32 qPCR serum samples from 183 patients with suspected leptospirosis. To establish the analytical sensitivity of the qPCR, experimentally spiked samples with known amounts of Leptospira interrogans were analyzed. Results: The analytical sensitivity of the qPCR was 102 leptospires/mL. In 98 patients MAT results were negative meanwhile 85 showed positive reactions, revealing acute infections. Twenty six acute-phase sera of these 85 patients showed a positive signal by qPCR (diagnostic sensitivity 30%). In these patients the average time between onset of symptoms and collection of the first sample was 8 days. In patients with negative results for qPCR and positive MAT results (n=59) the average interval between onset of symptoms and collection of the first sample was 13 days. The qPCR did not yield false positive results. Conclusions: The qPCR had a lower diagnostic sensitivity than MAT and a higher cost. However, it allowed to make an early diagnosis in 26 patients. In patients with confirmed acute infections and negative results by qPCR, more than 8 days had elapsed between the onset of the illness and extraction of the first serum sample. Our data support that the qPCR from sera have clinical utility within the first week of illness.

scholarly journals Evaluation of rapid, cassette immunochromatographic tests in the serological diagnosis of COVID-19

2021 ◽  
pp. 25-37
Author(s):  
Waldemar Rastawicki ◽  
Klaudia Płaza ◽  
Adam Pietrusiński
Keyword(s):  
Low Cost ◽  
Lateral Flow ◽  
Serological Diagnosis ◽  
Igg Antibodies ◽  
Serum Samples ◽  
Serological Tests ◽  
Negative Results ◽  
Lateral Flow Assays ◽  
Low Sensitivity ◽  
Positive Results

Introduction: Lateral flow assays (LFIA) are the technology behind low-cost, simple, rapid and portable detection devices popular in biomedicine. Lately, they are very common used in serodiagnosis of SARS-CoV-2 infections. The aim of the presented study was to assess the usefulness of selected LFIA in serological diagnosis of COVID-19. Methods: The usefulness of seven lateral flow assays in the serodiagnosis of COVID-19 was evaluated (VAZYME, DIAGNOSIS, PCL, INGEZIM, BIOSENSOR, ACCU-TELL, NOVAtest). The study used 107 serum samples obtained from 74 individuals with current SARS-CoV-2 infection confirmed by RT-PCR. The ELISA-IgG (Euroimmun) was used as the reference assay for sensitivity and specificity testing. Results: The highest percentage of positive results was obtained when searching for IgG antibodies with the NOVAtest (40.6%) and DIAGNOSIS (39.2%) sets and the lowest detection for the PCL set - 25.5%. In the case of searching for IgM antibodies in all sets, significantly lower percentages of positive results compared to the IgG class were recorded. In general, all lateral flow assays showed low sensitivity in relation to the Euroimmun ELISA-IgG. The DIAGNOSIS kit (64.5%) was characterized by the highest sensitivity, and the PCL kit was the lowest (38.7%). On the other hand, the specificity of all kits was very high, almost 100% in almost all cases. Conclusions: Lateral flow assays due to their low sensitivity are not suitable for quick diagnosis of the current SARS-CoV-2 infections and cannot be an alternative to genetic or even antigen tests. They may be used only to retrospectively test the presence of IgG antibodies. However, a negative results of LFIA in suspected disease or after vaccination should be confirmed by more sensitive serological tests.

scholarly journals Evaluation of Serum Cryptococcal Antigen Testing Using Two Novel Semiquantitative Lateral Flow Assays in Persons with Cryptococcal Antigenemia

2020 ◽  
Vol 58 (4) ◽  
Author(s):  
Caleb Skipper ◽  
Kiiza Tadeo ◽  
Emily Martyn ◽  
Elizabeth Nalintya ◽  
Radha Rajasingham ◽  
...  
Keyword(s):  
False Positive ◽  
Diagnostic Performance ◽  
False Negative ◽  
Lateral Flow ◽  
Reference Standard ◽  
Serum Samples ◽  
Cryptococcal Antigen ◽  
Negative Results ◽  
Lateral Flow Assays ◽  
Positive Results

ABSTRACT Early cryptococcal disease can be detected via circulating antigen in blood before fulminant meningitis develops, when early antifungal therapy improves survival. Two semiquantitative cryptococcal antigen (CrAg) lateral flow assays (LFAs) have been developed, but their diagnostic performance has not been defined. Cryopreserved serum samples from HIV-infected Ugandans obtained as part of a prospective CrAg-screening cohort were tested in duplicate for CrAg by the CrAgSQ (IMMY) and CryptoPS (Biosynex) lateral flow assays. Case-controlled diagnostic performance was measured using the FDA-approved CrAg LFA (IMMY) as a reference standard via McNemar’s test. Of 99 serum samples tested, 57 were CrAg positive (CrAg+) by the CrAg LFA reference standard. By CrAgSQ, 57 were read as positive, with 98% sensitivity (56/57; 95% confidence interval [CI], 0.91 to 0.99) and 98% specificity (41/42; 95% CI, 0.88 to 0.99) (McNemar’s, P = 0.99). The sample with a false-negative result by CrAgSQ (n = 1) had a titer of <1:5, while the sample with a false-positive result (n = 1) yielded a 1+ result. By CryptoPS, 52 samples were read as positive, with 88% sensitivity (50/57; 95% CI, 0.76 to 0.95) and 95% specificity (40/42; 95% CI, 0.84 to 0.99) (McNemar’s, P = 0.18). The CryptoPS false-negative results included samples with titers of <1:5 (n = 1), 1:5 (n = 5), and 1:20 (n = 1), while samples with false-positive results by CryptoPS (n = 2) yielded Positive results. The CryptoPS assay missed 35% (7/20) of samples with CrAg LFA titers of ≤1:20. The new semiquantitative CrAg LFAs allow rapid estimation of titer levels in easy-to-perform platforms. The CrAgSQ demonstrated better qualitative sensitivity and specificity than the CryptoPS compared to the reference standard. The exact grading of the CrAgSQ results has some subjectivity, with interreader variability; however, qualitative reads were generally concordant for both assays.

scholarly journals Active surveillance in poultry in Poland for avian influenza subtypes H5 and H7.

2014 ◽  
Vol 61 (3) ◽  
Author(s):  
Anna Pikuła ◽  
Krzysztof Smietanka ◽  
Anna Lisowska ◽  
Zenon Minta
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Serum Samples ◽  
Surveillance Programme ◽  
Negative Results ◽  
Hemagglutination Inhibition Test ◽  
Avian Influenza A Virus ◽  
Serological Surveillance ◽  
Positive Results ◽  
Free Status

A serological surveillance programme for avian influenza A virus (AIV) subtype H5 and H7 in poultry was implemented in Poland in 2008-2013 with two main objectives: i) to detect subclinical infections or previous exposures to AIV H5 and H7 subtypes and ii) to demonstrate the AI- free status of Poland. During this period, over 45 000 serum samples from 2833 holdings were examined using the hemagglutination inhibition test (HI). The presence of HI antibodies was detected in 8 breeder geese holdings (7 positive for H5 and 1 positive for H7 AIV) and in 1 breeder duck holding (H5-positive), which represented 0.32% of all investigated holdings. All seropositive flocks were examined by real time RT-PCR with negative results, which substantiated the AI-free status of Poland. Positive results detected in clinically healthy poultry kept in an open range system indicate prior infections with low pathogenic AIV originating from the wild-bird reservoir.

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.

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