scholarly journals A Case of Malaria Patient with SARS-CoV-2 Antibody False-Positive

2021 ◽  
Author(s):  
hong zhou
Keyword(s):  
Nucleic Acid ◽  
False Positive ◽  
Malaria Patient ◽  
Antibody Detection ◽  
Nucleic Acid Detection ◽  
Malaria Rapid Diagnostic Test ◽  
Igg Antibody ◽  
Case Presentation ◽  
Igm Antibody ◽  
Positive Results

Abstract Background: The SARS-CoV-2 antibody detection are used to diagnose or exclude suspected COVID-19 patients as a supplement to nucleic acid detection. False-positive results of SARS-CoV-2 antibody have been reported but rarely associated with malaria. A case of malaria patient with SARS-CoV-2 antibody false-positive is described.Case presentation: A 24 year-old male returned from Côte d’Ivoire was diagnosed Plasmodium falciparum by Malaria rapid diagnostic test. The patient had suspicious exposure to COVID-19. His SARS-CoV-2 IgM antibody was positive one day before admission and turned negative on the 18th day of admission, while the IgG antibody and nasopharyngeal swabs SARS-Cov-2 nucleic acid had been negative. Conclusion: Malaria might cause false positive for SARS-CoV-2 IgM antibody. A careful interpretation of the SARS-CoV-2 antibody result is useful to avoid wasting medical resources especially malaria-endemic areas.

scholarly journals Optimize Clinical Laboratory Diagnosis of COVID-19 from Suspect Cases by Likelihood Ratio of SARS-CoV-2 IgM and IgG antibody

2020 ◽  
Author(s):  
Feng Yangchun
Keyword(s):  
Nucleic Acid ◽  
Likelihood Ratio ◽  
Posterior Probability ◽  
Clinical Laboratory ◽  
Laboratory Diagnosis ◽  
Antibody Detection ◽  
Nucleic Acid Detection ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Antibody Tests

ObjectiveTo optimize clinical laboratory diagnosis of COVID-19 from suspect cases by Likelihood Ratio of SARS-CoV-2 IgM and IgG antibody.MethodsBy reinterpreting the data in the article “Diagnostic Value of Combined Detection of Serum 2019 novel coronavirus IgM and IgG Antibodies in novel coronavirusin Infection”, the positive likelihood ratio of IgM and IgG antibody in diagnosis of COVID-19 (nucleic acid positive patients) was calculated, and the posterior probability of IgM and IgG antibodies and their tandem detection to diagnose was finally calculated.ResultsThe positive likelihood ratios of single IgM and IgG antibody were 18.50 and 12.65 respectively, and the posterior probabilities were 90.18% and 86.26% respectively. However, the posterior probability of the two antibodies tandem detection is 99.15%, which can give clinicians quantitative confidence in the diagnosis of COVID-19 from suspected cases. According to the results of this study, combining the advantages and disadvantages of nucleic acid detection and antibody detection, the clinical pathway for clinicians to diagnose COVID-19 is found.ConclusionFor suspected cases, IgM and IgG antibody tests should be firstly done at the same time. If the antibody tests are all positive, COVID-19 can be confirmed. If not, nucleic acid detection (one or more times) is performed, and in extreme cases, high-throughput viral genome sequencing is performed.

scholarly journals Serological detection of 2019-nCoV respond to the epidemic: A useful complement to nucleic acid testing

2020 ◽  
Author(s):  
Jin Zhang ◽  
Jianhua Liu ◽  
Na Li ◽  
Yong Liu ◽  
Rui Ye ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Virus Disease ◽  
Roc Curves ◽  
Laboratory Diagnosis ◽  
Healthy People ◽  
Antibody Detection ◽  
Nucleic Acid Detection ◽  
Igg Antibodies ◽  
Igg Antibody ◽  
Epidemic Area

AbstractBackgroundPneumonia caused by 2019 novel coronavirus (2019-nCoV) was first reported in Wuhan, Hubei Province, China in December 2019. Then it has been reported in more than 20 countries and regions overseas rapidly. More than eighty thousand cases have been infected, resulting in more than three thousand deaths. Due to the limitation of nucleic acid detection, many clinical suspected cases cannot be diagnosed in time.MethodsWe used automated chemiluminescent immunoassay to detect serum IgM and IgG antibodies to 2019-nCoV of 736 subjects including confirmed Corona Virus Disease 2019 (COVID-19) patients, non-COVID-19 fever patients, other disease patients and medical staff as well as healthy people. The dynamic process of antibody production in COVID-19 disease progression were analyzed, and the value of antibody detection in the laboratory diagnosis of COVID-19 were evaluated.ResultsCOVID-19 patients were becoming reactive(positive) for specific anti-2019-nCoV IgM antibodies from 7-12 days after the onset of morbidity, followed closely by the IgG. The levels of specific IgM and IgG antibodies increased with the progression of the disease. The trend of IgM and IgG changes in different cases is not exactly the same. The levels of IgM and IgG and their distributions in different groups were different with that of healthy people. The areas under the ROC curves for IgM and IgG to diagnose COVID-19 were 0.988 and 1.000, respectively.ConclusionsSpecific IgM or IgG antibody detection had good sensitivity and specificity for the diagnosis of suspected fever cases. Detection of specific antibodies in patients with fever can be a good distinction between COVID-19 and other diseases in low epidemic area.

scholarly journals Performance verification of anti-SARS-CoV-2-specific antibody detection by using four chemiluminescence immunoassay systems

2020 ◽  
Vol 57 (6) ◽  
pp. 429-434
Author(s):  
Yafang Wan ◽  
Zhijie Li ◽  
Kun Wang ◽  
Tian Li ◽  
Pu Liao
Keyword(s):  
False Positive ◽  
Detection System ◽  
False Positive Rate ◽  
Antibody Test ◽  
The Other ◽  
Antibody Detection ◽  
Igg Antibody ◽  
Chi Square ◽  
Chemiluminescence Immunoassay ◽  
Chi Square Test

Objectives The purpose of the current study was to evaluate the analytical performance of seven kits for detecting IgM/IgG antibodies against coronavirus (SARS-CoV-2) by using four chemiluminescence immunoassay systems. Methods Fifty patients diagnosed with SARS-CoV-2 infection and 130 controls without coronavirus infection from the General Hospital of Chongqing were enrolled in the current retrospective study. Four chemiluminescence immunoassay systems, including seven IgM/IgG antibody detection kits for SARS-CoV-2 (A_IgM, A_IgG, B_IgM, B_IgG, C_IgM, C_IgG and D_Ab), were employed to detect antibody concentrations. The chi-square test, the receiver operating characteristic (ROC) curve and Youden’s index were determined to verify the cut-off value of each detection system. Results The repeatability verification results of the A, B, C and D systems are all qualified. D_Ab performed best (92% sensitivity and 99.23% specificity), and B_IgM performed worse than the other systems. Except for the A_IgM and C_IgG systems, the optimal diagnostic thresholds and cut-off values of the other kits and their recommendations are inconsistent with each other. B_IgM had the worst AUC, and C_IgG had the best diagnostic accuracy. More importantly, the B_IgG system had the highest false-positive rate for testing patients with AIDS, tumours and pregnancies. The A_IgM system test showed the highest false-positive rates among elderly individuals over 90 years old. COVID-2019 IgM/IgG antibody test systems exhibit performance differences. Conclusions The Innodx Biotech Total Antibody serum diagnosis kit is the most reliable detection system for anti-SARS-CoV-2 antibodies, which can be used together with nucleic acid tests as an alternative method for SARS-CoV-2 detecting.

scholarly journals Evaluation of Six Commercial Point-of-Care Tests for Diagnosis of Acute Dengue Infections: the Need for Combining NS1 Antigen and IgM/IgG Antibody Detection To Achieve Acceptable Levels of Accuracy

2011 ◽  
Vol 18 (12) ◽  
pp. 2095-2101 ◽  
Author(s):  
Stuart D. Blacksell ◽  
Richard G. Jarman ◽  
Mark S. Bailey ◽  
Ampai Tanganuchitcharnchai ◽  
Kemajittra Jenjaroen ◽  
...  
Keyword(s):  
Dengue Fever ◽  
Sensitivity And Specificity ◽  
Dengue Infection ◽  
Antibody Test ◽  
Antibody Detection ◽  
Sample Collection ◽  
Igg Antibody ◽  
Igm Antibody ◽  
Ns1 Antigen ◽  
Antibody Tests

ABSTRACTSix assays were evaluated in this study to determine their suitability for the diagnosis of acute dengue infection using samples from 259 Sri Lankan patients with acute fevers (99 confirmed dengue cases and 160 patients with other confirmed acute febrile illnesses): (i) the Merlin dengue fever IgG & IgM combo device (Merlin), (ii) the Standard Diagnostics Dengue Duo nonstructural 1 (NS1) antigen and IgG/IgM combo device (Standard Diagnostics, South Korea), (iii) the Biosynex Immunoquick dengue fever IgG and IgM (Biosynex, France) assay, (iv) the Bio-Rad NS1 antigen strip (Bio-Rad, France), (v) the Panbio Dengue Duo IgG/IgM Cassette (Inverness, Australia), and (vi) the Panbio dengue NS1 antigen strip (Inverness, Australia). The median number of days of fever prior to admission sample collection was 5 days (interquartile range, 3 to 7 days). Sensitivity and specificity of the NS1 antigen tests ranged from 49 to 59% and from 93 to 99%, respectively, and sensitivity and sensitivity of the IgM antibody test ranged from 71 to 80% and from 46 to 90%, respectively. Combining the NS1 antigen and IgM antibody results from the Standard Diagnostics Dengue Duo test gave the best compromise of sensitivity and specificity (93% and 89%, respectively) and provided the best sensitivity in patients presenting at different times after fever onset. The Merlin IgM/IgG antibody tests correctly classified 64% and 86% of the primary and secondary dengue infection cases, respectively, and the Standard Diagnostics IgM/IgG antibody tests correctly classified 71% and 83% of the primary and secondary dengue infection cases, respectively. This study provides strong evidence of the value of combining dengue antigen- and antibody-based test results in the rapid diagnostic test (RDT) format for the acute diagnosis of dengue.

scholarly journals Diagnostic value of serum Aspergillus IgG antibody for invasive pulmonary aspergillosis and chronic pulmonary aspergillosis in non-agranulocytic patients

2020 ◽  
Author(s):  
Qihong Yu ◽  
Jingdong He ◽  
Bin Xing ◽  
Xin Li ◽  
Hongyu Qian ◽  
...  
Keyword(s):  
Bacterial Pneumonia ◽  
Invasive Pulmonary Aspergillosis ◽  
Roc Curves ◽  
Antibody Detection ◽  
Healthy Controls ◽  
Igg Antibody ◽  
Pulmonary Aspergillosis ◽  
Igm Antibody ◽  
Positive Rate ◽  
Chronic Pulmonary Aspergillosis

Abstract Background: At present, serum Aspergillus IgG and IgM antibody detection is mainly used in the diagnosis of chronic pulmonary aspergillosis (CPA), but its value in the diagnosis of invasive pulmonary aspergillosis (IPA) in non-agranulocytic patients is still unclear. IgG is a marker of long-term infection and is used to assist in the diagnosis of pre-existing or chronic infection-related diseases. The aim of this study was to investigate and compare the value of serum Aspergillus IgG and IgM antibody detection in the diagnosis of IPA and CPA in non-agranulocytic patients. Methods: Fifty-eight cases of pulmonary aspergillosis (37 IPA and 21 CPA cases), 15 cases of community-acquired bacterial pneumonia and 50 cases in the healthy control group were collected. The serum (1,3)-β-D-glucan test (G test) was performed with a chromogenic method, and the galactomannan test (GM test) and Aspergillus IgG and IgM antibody detection were performed by commercial enzyme-linked immunosorbent assay (ELISA) in all patients. The sensitivity and specificity, cut-off value and area under the curve (AUC) of Aspergillus IgG and IgM antibodies were further obtained by receiver operating characteristic (ROC) curves. Results: The positive rate of the G test, Aspergillus IgG antibody detection and the GM test also showed notable differences among the IPA, CPA, community-acquired bacterial pneumonia and healthy groups ( P = 0.006, P < 0.001 and P = 0.217, respectively). Only the positive rate of the GM test showed a significant difference between the IPA and CPA groups ( P = 0.04). ROC curves indicated that Aspergillus IgG antibody detection had a higher specificity in the IPA group than in the CPA group (0.952). The detection of Aspergillus IgG antibody can preferably distinguish IPA from community-acquired bacterial pneumonia and healthy controls (sensitivity = 0.923, specificity = 0.459, cut-off value = 134.46, AUC = 0.727). It can also distinguish CPA from community-acquired bacterial pneumonia and healthy controls (sensitivity = 0.952, specificity = 0.692, cut-off value = 75.46, AUC = 0.873). Conclusions: Serum Aspergillus IgG antibody detection may have certain clinical value in the diagnosis of IPA and CPA in non-agranulocytic patients.

scholarly journals Distribution characteristics of SARS-CoV-2 IgM and IgG in false-positive results detected by Chemiluminescent immunoassay

2021 ◽  
Author(s):  
Yan Lei ◽  
Xiaolan Lu ◽  
Daiyong Mou ◽  
Qin Du ◽  
Guo Bin ◽  
...  
Keyword(s):  
False Positive ◽  
Dynamic Monitoring ◽  
Antibody Detection ◽  
Distribution Characteristics ◽  
Igg Antibodies ◽  
Dynamic Changes ◽  
Positive Proportion ◽  
Chemiluminescent Immunoassay ◽  
False Positive Probability ◽  
Positive Results

Abstract There have been several false-positive results in the antibody detection of the COVID-19. This study aims to analyze the distribution characteristics of SARS-CoV-2 IgM and IgG in false-positive results detected using chemiluminescent immunoassay. The characteristics of the false-positive results in SARS-CoV-2 IgM and IgG testing were retrospectively analyzed. The dynamic changes in the results of SARS-CoV-2 IgM and IgG antibodies were observed. The false-positive proportion of the single SARS-CoV-2 IgM positive results was 95.88%, which was significantly higher than those of the single SARS-CoV-2 IgG positive results (67.50%) (P < 0.001) and SARS-CoV-2 IgM & IgG positive results (29.55%) (P < 0.001). The S/CO of the SARS-CoV-2 IgM and IgG in false-positive results ranged from 1.0 to 50.0. The false-positive probability of SARS-CoV-2 IgM in the S/CO range (1.0 ~ 3.0) was 91.73% (77/84), and the probability of false-positive of SARS-CoV-2 IgG in the S/CO range (1.0 ~ 2.0) was 85.71% (24/28). Dynamic monitoring showed that the S/CO values of IgM in false-positive results decreased or remained unchanged, whereas the S/CO values of IgG in false-positive results only decreased. The possibility of false-positive of the single SARS-CoV-2 IgM positive and single SARS-CoV-2 IgG positive results was high. As the value of S/CO decreased, the probability of false-positive consequently increased, especially among the single SARS-CoV-2 IgM positive results.

scholarly journals The Mechanics of the "L.E." Cell Phenomenon, Studied with a Simplified Test

Blood ◽  
1955 ◽  
Vol 10 (7) ◽  
pp. 718-729 ◽  
Author(s):  
I. SNAPPER ◽  
DANIEL J. NATHAN
Keyword(s):  
Nucleic Acid ◽  
Inclusion Body ◽  
Lupus Erythematosus ◽  
False Positive ◽  
Cell Formation ◽  
Living Cells ◽  
Simple Method ◽  
Large Numbers ◽  
The Difference ◽  
Positive Results

Abstract 1. A simple method is described for the formation of large numbers of lupus cells by positioning one drop of finger or ear blood of a lupus patient upon an accumulation of dried, normal polynuclear leukocytes. Thick leukemic smears and perhaps even imprints of various carcinomas or Hodgkin’s tissue can also be used as substrates. 2. No false positive results were obtained in a group of control patients. 3. Striking results were obtained with this method itt 20 of 21 known cases of disseminated lupus erythematosus. The remaining case in whom a single "L.E." cell was found by a conventional method, to date has yielded no lupus cells by our method. 4. The difference in appearance of the inclusion body of some of these cells from the characteristic Hargraves cell is highlighted. 5. Theoretic considerations of the mechanism of lupus cell formation are discussed and reassessed in the light of our experience with this method. For the formation of "L.E." cells it seems necessary that living polynuclear leukocytes, dead cells and lupus serum be brought together. The lupus serum can depolymerize the desoxyribose nucleic acid of the nuclei of the dead cells, but not of living cells. The depolymerized material is then phagocytized by living polynuclear cells and formation of lupus cells results.

Comparison of the Nucleic Acid Amplification System NASBA® and Agar Isolation for Detection of Pathogenic Campylobacters in Naturally Contaminated Poultry

1996 ◽  
Vol 59 (7) ◽  
pp. 683-687 ◽  
Author(s):  
M. UYTTENDAELE ◽  
R. SCHUKKINK ◽  
B. VAN GEMEN ◽  
J. DEBEVERE
Keyword(s):  
Nucleic Acid ◽  
False Positive ◽  
Detection System ◽  
False Negative ◽  
Isolation Procedure ◽  
Nucleic Acid Amplification ◽  
True Nature ◽  
Selective Enrichment ◽  
Amplification System ◽  
Positive Results

A total of 160 poultry products were examined for the presence of pathogenic campylobacters using the traditional agar isolation method and the nucleic acid amplification system NASBA®, both after a 24-h selective enrichment. Pathogenic campylobacters could be isolated from 92 of 160 (57.5%) samples using agar isolation, among which 79 (49.37%) were identified as Campylobacter jejuni, six (3.75%) as C. coli, five (3.12%) as C. lari, and two (1.25%) as unclassified. The NASBA® assay provides a specific and sensitive method for detection of these campylobacters. A total of 149 samples (93.12%) gave similar results for both the traditional isolation procedure on modified Campylobacter charcoal desoxycholate agar and the NASBA® enzyme-linked gel assay detection system. Two false-negative results were obtained with the agar isolation procedure. Nine false-positive results were reported when the NASBA® system was used. However, the high sensitivity of the NASBA® method and indications that in some cases the traditional isolation procedure failed (abundance of a contaminating noncampylobacter bacteria which grew on the Campylobacter selective media) raises doubt about the true nature of these false-positive results. The NASBA® detection assay offers a rapid and useful analytical method when screening for the presence of pathogenic campylobacters. The complete procedure, including 24 h of selective enrichment, required 32 h.

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