Sensitivity Of IgM Research Articles

Clinical characteristics of enteric fever and performance of TUBEX TF IgM test in Indonesian hospitals.

Accurate diagnosis of enteric fever is challenging, particularly in low- and middle-income countries, due to the overlap of clinical and laboratory features with other pathogens. To better understand the difficulties in enteric fever diagnosis, we evaluated the characteristics of patients clinically diagnosed with enteric fever and the real-world performance of TUBEX TF, one of the most used tests in Indonesia. Patients were recruited through the AFIRE (Etiology of Acute Febrile Illness Requiring Hospitalization) study at eight Indonesian hospitals. Blood culture was performed for all patients, and TUBEX TF was performed for suspected enteric cases. Salmonella PCR and ELISA tests were performed at a reference lab. Sensitivity and specificity of TUBEX TF and IgM and IgG anti-S. Typhi ELISA were determined. Of 301 patients clinically diagnosed with enteric fever, 50 (16.6%) were confirmed by blood culture and/or PCR. Confirmed cases were mostly school-aged children presenting with fever, anorexia, dizziness and/or abdominal pain with normal leukocyte count or leukopenia. TUBEX TF demonstrated a sensitivity of 97.6% to 70.7% and specificity of 38.3% to 67.2% at cutoffs of 4 and 6, respectively. Acute IgG demonstrated the best sensitivity and specificity, at 90.7% and 82.7%, respectively, and the best ROC characteristics. A substantial proportion of enteric fever was misdiagnosed at all study hospitals, likely due to the overlap of clinical characteristics and lab parameters with those of other common pathogens. The TUBEX TF rapid serological assay demonstrated suboptimal performance in our setting and tended to over-diagnose enteric fever. The role of IgG from acute specimens for identification of enteric fever cases merits additional consideration.

Brucellosis of the spine – A global public health problem - An analysis of 37 patients from a ‘high risk’ region

BackgroundBrucellosis is a global public health issue. Brucellosis of the spine presents as a wide spectrum. The aim was to present the outcome analysis of patients treated for Spinal Brucellosis in the endemic region. Secondly to assess the accuracy of IgG and IgM Elisa in the diagnosis. ResultsA retrospective study of all patients who were treated for Brucellosis of the spine from 2010 to 2020 was conducted. Confirmed cases of Brucellosis of spine and who had adequate follow up after completion of treatment were included. The outcome analysis was based on clinical, laboratory and radiological parameters. There were 37 patients enrolled with a mean age of 45 and an average follow up of 24 months. All of them presented with pain and 30% had neurological deficits. Surgical intervention was done in 24%(9/37patients). All the patients were treated with triple drug regimen for an average duration of 6 months. Those patients with relapse had a 14month period of triple drug regimen. The sensitivity and specificity of IgM was 50% and 85.71%. The sensitivity and specificity of IgG was 81.82% and 7.69%.76% of them had good functional outcome and 82% of them had near normal neurological recovery and 97.3%(36 patients) were healed of the disease with relapse in one patient(2.7%). ConclusionsMajority (76%) of the patients with Brucellosis of the spine were treated conservatively. Average duration of treatment of triple drug regimen was 6 months. The sensitivity of IgM & IgG was 50% and 81.82% The specificity of IgM and IgG was 85.71% and 7.69% respectively.

Clinical Application of SARS-CoV-2 IgM and IgG Antibody Detection Using the Colloidal Gold Immunochromatography Assay

Objective: The COVID-19 pandemic, which was caused by SARS-CoV-2, has had a significant effect on global public health, economies, and societies worldwide. Serum antibody testing is a critical method for the diagnosis of COVID-19 and can complement RT-PCR in the diagnosis of COVID-19 patients; however, the performance of rapid antibody assays in the clinical setting has not been established. Methods: Rapid antibody assays were evaluated by investigating 296 COVID-19-positive individuals and 542 negative individuals confirmed by clinical diagnosis. The clinical diagnostic results were used as controls to evaluate the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), kappa, and 95% confidence interval (CI) of the rapid tests. Result: IgM-positivity had a sensitivity of 86.1% and specificity of 99.1%. IgG-positivity had a sensitivity of 86.5% and specificity of 98.7%. The sensitivity of combined IgM- and IgG-positivity in clinically confirmed patients was 73.1% in the early stage (1-7 days after symptom onset) and reached 99% 15 days after symptom onset. The concordance between rapid antibody-positive tests and clinical diagnosis-positivity had a kappa value of 0.93. In addition, the false-positive rate of IgM and IgG combined nucleic acid detection was 30% in the early stage. Conclusion: The combined use of IgM and IgG could serve as a more suitable alternative detection method for patients with COVID-19. The rapid antibody test can be considered as an excellent supplementary approach for detecting SARS-CoV-2 in clinical application.

A systematic review and meta-analysis on the accuracy of rapid immunochromatographic tests for dengue diagnosis.

Rapid immunochromatographic tests are frequently used to diagnose dengue due to their easy use, low cost, and fast response. A high level of accuracy is essential for rapid diagnostic tests to support their large-scale use. Thus, this systematic review aims to evaluate the accuracy of rapid dengue diagnostic tests. The investigation was run through the following databases: LILACS, Medline (Pubmed), CRD, The Cochrane Library, Trip Medical Database, and Google Scholar. To solve difficulties, two independent reviewers performed document screening and selection. ELISA assay was adopted as a reference test because of several methodologic advantages. Seventeen articles were included accordingly, reckoning 6837 participating individuals. The receiver operating characteristic (ROC) and Forest Plot were conducted to evaluate the sensitivity and specificity for each analyzed parameter (anti-dengue IgM, IgG, and NS1 antigen). The risk of bias and quality of evidence were assessed as moderate using QUADAS-2 and Grading of Recommendations Assessment, Development, and Evaluation (GRADE), respectively. The sensitivity of IgM concerning the studied tests ranged from 13.8 to 90%, while that of NS1 ranged from 14.7 to 100% (95% CI). The antibodies with NS1 presented increased sensitivity; pooled data show that the association of the three analytes bestows the best result, with a combined sensitivity of 90% (CI 95%: 87-92%) and a pooled specificity of 89% (CI 95%: 87-92%). Thus, the present review provides relevant knowledge for decision-making between available rapid diagnostic tests.

The epidemiology, clinical characteristics, and macrolide susceptibility of Mycoplasma pneumoniae pneumonia in children in Southern Taiwan, 2019-2020.

Since the global use of the pneumococcal conjugate vaccine, Mycoplasma pneumoniae (MP) has become the most common bacterial cause of lower respiratory tract infections among children. Monitoring the changing epidemiology and antimicrobial resistance rates of this organism is important for MP clinical management. This study characterizes key features of MP during the 2019-2020 epidemic in children in Taiwan. The cohort included all hospitalized children under 18 years of age with polymerase chain reaction (PCR)-confirmed community-acquired mycoplasma pneumonia (CAMP) in southern Taiwan. Macrolide resistance was identified by mutations in domain V of MP 23S rRNA. Severe disease referred to symptoms warranting oxygen therapy, septic shock, or intensive care unit admission. Among 495 LRTI patients, 195 (39.4%) had CAMP, of which 106 (54.4%) had concurrent serological evidence of MP infection. The diagnostic sensitivity of IgM in the acute phase was 65.6%. CAMP case numbers were highest from July 2019 to January 2020. The most common clinical presentations of CAMP were fever (99.0%), cough (99.0%), and coryza (31.8%). Despite a high rate of macrolide resistance (88.1%), macrolide-resistant MP (MRMP) did not differ from macrolide-sensitive MP (MSMP) in clinical course or severity. Delayed administration of effective antimicrobial treatment was also associated with severe disease (p<0.05). Early diagnosis and determination of MRMP are needed for effective management of MP infection.

Literatur Review: Perbandingan Hasil Diagnosis Laboratorium IgM, IgG SARS-CoV-2 Metode ELISA Dan ICT

Background: The use of COVID-19 test kit depends on the sensitivity and specificity to detect and provide an accurate COVID-19 diagnosis. Currently, there are many serology tests detecting Antibody of SARS-CoV-2, that the evidence for its accuracy is still being studied through various evidence research. Purpose: Compare the sensitivity and specificity of the ELISA and ICT method for IgM, IgG SARS-CoV-2 detection. Method : literature review with Preferred Reporting Items for Systematic Reviews and Meta-Analyzes (PRISMA) statement guideline. 10 out of 176 studies were obtained from searches which are carried out in PubMed, Science Direct and Google Scholar between October and December 2020. Articles were independently screened by title, abstract and full-text using the PICOS framework and critically appraised using JBI Critical Appraisal Tools. Findings were descriptively analyzed. Result : , Comparison of ELISA and ICT sensitivity in detecting IgM, IgG SARS-CoV-2 was 76,3%, 77,3% and ICT method : 53,9%, 64,8%. While the specificity of the ICT method was 96,2%, 98,1% and ELISA method : 94%, 97,1%. Conclusion: The sensitivity of IgM, IgG SARS-CoV-2 detection using ELISA method was higher than the ICT method. Conversely, the specificity of the ICT method (97.1%) is higher than the ELISA method (95.5%)

Clinical Sensitivity, Specificity and Epidemiology of SARS-CoV-2 Serological Testing Using the Biozek COVID-19 Test.

Background: Clinical validation using the Biozek COVID-19 test including sensitivity and specificity and associated patient-reported symptoms with SARS-CoV-2 seropositivity. Methods: 316 sera were analyzed including 47 hospitalized cases, 50 mild cases and 219 negative controls. Results were read visually by two technicians and in case of discrepancy by a third. Models were created between independent variables and IgG seropositivity using multivariable logistic regression analysis. Results: Sensitivity of both IgM and IgG together for hospitalized patients at all time periods was 68.1% (32/47) and 90.0% (27/30) after 10 days or more. From mild/asymptomatic cases the combined IgM and IgG sensitivity was 92.0% (46/50) and 91.8% (45/49) after 10 days or more. In the group of non-COVID-19 cases, the overall specificity was 99.1% (217/219). For IgG alone, the specificity was 99.5% (218/219). In the multivariable analysis loss of smell remained the strongest associated variable with an odds ratio (95%CI): 6.82 (5.61–8.31), p-value < 0.001. Our final prediction model yielded a ROC-AUC of 0.77 (0.74–0.81) showing acceptable discrimination. Conclusions: The Biozek COVID-19 test showed high specificity and good sensitivity 10 days after the first sickness day. Solely IgM positive tests must be interpreted with caution and preferably excluded. In order to capture most symptomatic COVID-19 cases, loss of smell should be included within symptomatic screening policies.

Serological Differences after Acute Zika Virus Infections between Children and Adults: Implication for Use of a Serological Test.

Information is limited regarding differential serological responses after acute Zika virus (ZIKV) infections and prevalence of cross-reactivity with anti-dengue virus (DENV) assays comparing children and adults. Early convalescent sera from a cohort of suspected mild DENV cases between December 2016 and September 2018 at Bamrasnaradura Infectious Diseases Institute in Thailand were tested for nonstructural protein 1 (NS1)-based anti-ZIKV IgM and IgG ELISAs (Euroimmun), and in-house anti-DENV IgM- and IgG-capture ELISAs. ZIKV cases were identified by positive real-time reverse transcriptase-polymerase chain reaction on urine. Sera from 26 (10 children and 16 adults) ZIKV and 227 (153 children and 74 adults) non-ZIKA cases collected at the median duration of 18 days (interquartile range [IQR] 18,19) post-onset of symptoms were tested. Comparing pediatric ZIKV to adult ZIKV cases, the mean anti-ZIKV IgM ratio was higher (2.12 versus 1.27 units, respectively; P = 0.07), whereas mean anti-ZIKV IgG ratio was lower (3.13 versus 4.24 units, respectively; P = 0.03). Sensitivity of anti-ZIKV IgM and specificity of anti-ZIKV IgG in pediatric ZIKV were higher than in adult ZIKV cases (80.0% versus 43.7% and 79.1% versus 43.2%, respectively). No cross-reactivity with anti-DENV IgM- and IgG-capture ELISA were reported in pediatric ZIKV cases in our study, whereas 25% and 12.5% were found in adult ZIKV cases, respectively. Age-related ZIKV serological differences have been observed. Positive NS1-based anti-ZIKV IgM and IgG ELISA at the early convalescent phase could be useful for ZIKV diagnosis in children, even in a dengue endemic setting.

Assessment of severity and mortality of COVID‐19 with anti‐A1 and anti‐B IgM isohaemagglutinins, a reflection of the innate immune status

AimsThe relationship between the innate immune system that creates the polysaccharide antibody response and COVID‐19 is not fully understood. In this study, it was aimed to determine the predictive values of isohaemagglutinins in COVID‐19 severity/mortality.MethodsApproximately 15 440 patients diagnosed with COVID‐19 were examined, and a total of 286 patients with anti‐B and anti‐A1 IgM isohaemagglutinins test results were randomly enrolled in the study. These patients were stratified into two groups according to anti‐A1 (n: 138 blood type B or O) and anti‐B (n: 148 blood type A) IgM isohaemagglutinins. Anti‐A1 or/and anti‐B IgM, biochemical parameters, symptoms, chronic diseases, hospitalisation status, intubation status, admission to intensive care unit (ICU) and exitus status were recorded and evaluated for all patients.ResultsAnti‐A1 IgM and anti‐B IgM were significantly lower in ICU patients (7.5 ± 9.9 vs 18.0 ± 20.4 and 5.5 ± 6.3 vs 19.3 ± 33.6 titres, respectively; P < .01) and in exitus patients (3.8 ± 3.6 vs 16.7 ± 18.7 and 3.5 ± 4.7 vs 16.9 ± 29.6 titres respectively; P < .01). In the ROC analysis performed to differentiate between exitus and discharge within groups, the sensitivity of anti‐B IgM and anti‐A1 IgM at cut‐off ≤4 was 88.9% and 79.6%, specificity 66.0% and 73.4%, and AUC 0.831 and 0.861, respectively (P < .01). Anti‐A1 IgM decreased the mortality risk 0.811 times per unit while anti‐B IgM decreased 0.717 times (P < .01).ConclusionAnti‐B and anti‐A1 isohaemagglutinins, which are an expression of the innate immune system, can be used to predict the severity and mortality of COVID‐19 disease.

Point-Of-Care clinical evaluation of the Clungene® SARS-CoV-2 virus IgG/IgM 15-minute rapid test cassette with the Cobas® Roche RT-PCR platform in patients with or without Covid-19

Background: Coronavirus disease 2019 (Covid-19) remains a pandemic with multiple challenges to confirm patient infectivity: lack of sufficient tests, accurate results, validated quality, and timeliness of results. We hypothesize that a rapid 15-minute Point-Of-Care serological test to evaluate past infection complements diagnostic testing for Covid-19 and significantly enhances testing availability. Method: A three arm observational study at Sharp Healthcare, San Diego, California was conducted using the Clungene® lateral flow immunoassay (LFI) and compared with the Cobas® Roche real-time polymerase chain reaction (RT-PCR) results. Arm 1: Thirty-five (35) subjects with confirmed Covid-19 using RT-PCR were tested twice: prior to 14 days following symptom onset and once between 12 and 70 days. Arm 2: Thirty (30) subjects with confirmed Covid-19 using RT-PCR were tested 12-70 days post symptom onset. Arm 3: Thirty (30) subjects with a negative RT-PCR for Covid-19 were tested 1–10 days following the RT-PCR test date. Results: Specificity of confirmed negative Covid-19 by RT-PCR was 100% (95% CI, 88.4%–100.0%); meaning there was 100% negative positive agreement between the RT-PCR and the Clungene® serological test results. Covid-19 subjects tested prior to day 7 of symptom onset were antibody negative. In subjects 7–12 days following symptom onset with a confirmed positive Covid-19 by RT-PCR, the combined sensitivity of IgM and IgG was 58.6% (95% CI, 38.9%–76.5%). In subjects 13–70 days following symptom onset with a confirmed positive Covid-19 by RT-PCR, the combined sensitivity of IgM and IgG was 90.5% (95% CI, 80.4%–96.4%). Conclusion: The Clungene® lateral flow immunoassay (LFI) is a useful tool to confirm individuals with an adaptive immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) indicating past infection. Providing Point-Of-Care results within 15 minutes without any laboratory instrumentation or specialized software has an added value of increasing test availability to patients who have been symptomatic for more than 1 week to confirm past infection. Performance characteristics are optimal after 13 days with a sensitivity and specificity of 90% and 100%, respectively. Statement of novelty: Formal controlled clinical studies of Covid-19 antibody tests have been limited. This study demonstrates the utility of the 15 minute rapid Clungene® test and the potential for expanded use where Covid-19 RT-PCR testing and vaccination is limited.

Sensitivity of IgM and IgG serology for SARS-CoV-2 plus physicians' gestalt or rRT-PCR for COVID-19 diagnosis

article: Sensitivity of IgM and IgG serology for SARS-CoV-2 plus physicians’ gestalt or rRT-PCR for COVID-19 diagnosis - Italian Journal of Emergency Medicine 2021 April;10(1):24-9 - Minerva Medica - Journals

Clinical significance of the serum IgM and IgG to SARS-CoV-2 in coronavirus disease-2019.

ObjectiveTo explore the clinical value of serum IgM and IgG to SARS‐CoV‐2 in COVID‐19.Methods105 COVID‐19 patients were enrolled as the disease group. 197 non‐COVID‐19 patients served as the control group. Magnetic chemiluminescent immunoassay (MCLIA) was used to detect the IgM and IgG.ResultsThe peak of positive rates of SARS‐CoV‐2 IgM was about 1 week earlier than that of IgG. It reached to peak within 15–21 days and then began a slowly decline. The positive rates of IgG were increased with the disease course and reached the peak between 22 and 39 days. The differences in sensitivity of the three detection modes (IgM, IgG, and IgM + IgG) were statistically significant. The largest group of test cases (illness onset 15–21 days) showed that the positive rate of IgG was higher than IgM. Also, the sensitivity of IgM combined with IgG was higher than IgM or IgG. IgM and IgG were monitored dynamically for 16 patients with COVID‐19, the results showed that serological transformation of IgM was carried out simultaneously with IgG in seven patients, which was earlier than IgG in four patients and later than IgG in five patients.ConclusionThe detection of SARS‐CoV‐2 IgM and IgG is very important to determine the course of COVID‐19. Nucleic acid detection combined with serum antibody of SARS‐CoV‐2 may be the best laboratory indicator for the diagnosis of SARS‐CoV‐2 infection and the phrase and predication for prognosis of COVID‐19.

Clinical validation of an immunochromatographic SARS-Cov-2 IgM/IgG antibody assay with Japanese cohort.

The coronavirus disease 2019 (COVID-19) has become a major health threat. To overcome COVID-19, appropriate diagnosis methods are urgently needed. The aim of this study was to clinically evaluate the colloidal gold immunochromatography assay for SARS-Cov-2 IgM/IgG antibody (Ab). Patients confirmed COVID-19 (n = 51) were recruited prospectively from the Musashino Red Cross hospital and Tokyo Medical and Dental University Medical Hospital, between March and May 2020. And the analytical specificity was assessed with serum samples of patients without COVID-19 (n = 100) collected between August to September 2019 before SARS-CoV-2 was first reported in China. Among COVID-19 patients, a total of 87 serum samples were tested for SARS-Cov-2 IgM/IgG Ab assay. IgM was detected 71.0 %, 86.9 %, and 83.3 % at day8-14, 15-28, >29 after symptom onset and IgG was detected in 81.6 %, 87.0 %, and 94.4 %, respectively. The sensitivity of IgM and IgG Ab after day8 assay was significantly higher than before day7, respectively (p=0.0016, 0.0003). There were no positive results in 100 serum samples from patients without COVID-19. The SARS-Cov-2 IgM/IgG Ab assay had 79.7% / 86.1% sensitivity (the 8 days after from onset) and 100% specificity in this population.

Diagnostic efficacy of anti-SARS-CoV-2 IgG/IgM test for COVID-19: A meta-analysis.

The serological testing of anti‐SARS‐CoV‐2 immunoglobulin G (IgG) and/or IgM is widely used in the diagnosis of COVID‐19. However, its diagnostic efficacy remains unclear. In this study, we searched for diagnostic studies from the Web of Science, PubMed, Embase, CNKI, and Wanfang databases to calculate the pooled diagnostic accuracy measures using bivariate random‐effects model meta‐analysis. As a result, 22 from a total of 1613 articles, including 2282 patients with SARS‐CoV‐2 and 1485 healthy persons or patients without SARS‐CoV‐2, were selected for a meta‐analysis. Pooled sensitivity, specificity, and area under curve of the summary receiver operator curve (SROC) were: (a) 0.85 (95% confidence interval [CI]: 0.79‐0.90), 0.99 (95% CI: 0.98‐1.00), and 0.99 (95% CI: 0.97‐0.99) for anti‐SARS‐CoV‐2 IgG and (b) 0.74 (95% CI: 0.65‐0.81), 0.99 (95% CI: 0.97‐1.00), and 0.95 (95% CI: 0.93‐0.97) for IgM. A subgroup analysis among detection methods indicated the sensitivity of IgG and IgM using enzyme‐linked immunosorbent assay were slightly lower than those using gold immunochromatography assay (GICA) and chemiluminescence immunoassay (P > .05). These results showed that the detection of anti‐SARS‐CoV‐2 IgG and IgM had high diagnostic efficiency to assist the diagnosis of SARS‐CoV‐2 infection. And, GICA might be used as the preferred method for its accuracy and simplicity.

Establishing a high sensitivity detection method for SARS-CoV-2 IgM/IgG and developing a clinical application of this method

ABSTRACT COVID-19 is caused by SARS-CoV-2 infection and was initially discovered in Wuhan. This outbreak quickly spread all over China and then to more than 20 other countries. SARS-CoV-2 fluorescent microsphere immunochromatographic test strips were prepared by the combination of time-resolved fluorescence immunoassay with a lateral flow assay. The analytical performance and clinical evaluation of this testing method was done and the clinical significance of the testing method was verified. The LLOD of SARS-CoV-2 antibody IgG and IgM was 0.121U/L and 0.366U/L. The specificity of IgM and IgG strips in healthy people and in patients with non-COVID-19 disease was 94%, 96.72% and 95.50%, 99.49%, respectively; and sensitivity of IgM and IgG strips for patients during treatment and follow-up was 63.02%, 37.61% and 87.28%, 90.17%, respectively. The SARS-CoV-2 antibody test strip can provide rapid, flexible and accurate testing, and is able to meet the clinical requirement for rapid on-site testing of virus. The ability to detect IgM and IgG provided a significant benefit for the detection and prediction of clinical course with COVID-19 patients.

Comparison of Helicobacter pylori stool antigen, salivary IgG, serum IgG, and serum IgM as diagnostic markers of H. pylori infection in children

Various non-invasive diagnostic tests are available for the detection of Helicobacter pylori infection. The aim of this study was to compare the sensitivity and specificity of HpSA, salivary IgG, serum IgG, and serum IgM to those of endoscopic-biopsy as the gold standard for the diagnosis of H. pylori infection. This is a cross-sectional study performed among pediatric patients at Dr. Soetomo General Hospital (Surabaya, Indonesia). Fecal, blood, and saliva samples were collected from all subjects. The results of the HpSA, salivary IgG, serum IgG, and serum IgM tests were compared to the results of endoscopic-biopsy as the gold standard. Of the 37 study participants, H. pylori infection was confirmed in 5 (13.33%) with serum IgG, 23 (63.33%) with serum IgM, 15 (40%) with HpSA, and 26 (70.97%) with salivary IgG. The salivary IgG enzyme-linked immunosorbent assay (ELISA) was the only diagnostic test with significantly different results, as compared to biopsy (p = 0.017). The results of this study showed that HpSA, salivary IgG, and serum IgG and IgM were not sufficient to replace endoscopic-biopsy as the gold standard for the diagnosis of H. pylori infection.

Development, optimization, and validation of an in-house Dot-ELISA rapid test based on SAG1 and GRA7 proteins for serological detection of Toxoplasma gondii infections.

BackgroundThe aim of the present study was to develop a simple, portable, and rapid assay for serodiagnosis of toxoplasmosis based on recombinant Toxoplasma gondii (T. gondii) SAG1 (rSAG1) and GRA7 (rGRA7) proteins.MethodsThe rSAG1 and rGRA7 proteins were expressed in Escherichia coli (E. coli) and purified in a single step by immobilized metal ion affinity chromatography. The immunoreactivity of the recombinant antigens was tested in an in-house IgG and IgM Dot enzyme-linked immunosorbent assay (Dot-ELISA) for potential use in serodiagnosis of T. gondii infection.ResultsResults from the comparison of in-house rSAG1-Dot-ELISA with ELISA for the detection of anti-Toxoplasma IgG and IgM include sensitivity of 83.7% and 81.2%, specificity of 90.2% and 89.3%, positive predictive values of 85.9% and 68.4%, and negative predictive values of 88.6% and 94.3%, respectively. Sensitivity of 66.2%, specificity of 81.2%, positive predictive values of 71.6%, and negative predictive values of 77.1% were concluded from in-house IgG rGRA7-Dot-ELISA. The sensitivity and specificity of IgM rGRA7-Dot-ELISA included 87.5% and 83.9%, respectively. Sensitivity and specificity of in-house Dot-ELISA for a combination of rSAG1 and rGRA7 included 87.5% and 91.1% for IgG and IgM, respectively. Sensitivity and specificity of a combination of rSAG1 and rGRA7 for the detection of IgM in suspected sera to acute toxoplasmosis were higher than those for the detection of IgG in sera with chronic infections (90.6% and 92% instead of 86.2% and 91.6%, respectively).ConclusionThe highlighted parameters of combined recombinant proteins were more significant than those of single recombinant proteins in in-house Dot-ELISA. These data suggest that the in-house Dot-ELISA based on rSAG1 and rGRA7 combination is a promising diagnostic tool with a similar sensitivity to the native antigens of T. gondii, which can be used for the serodiagnosis of toxoplasmosis in fields as well as less equipped laboratories.

Emergence of Attenuated Measles Illness Among IgG-positive/IgM-negative Measles Cases: Victoria, Australia, 2008-2017.

Waning measles immunity among vaccinated individuals may result in an attenuated illness. This study compares the epidemiological, clinical, and laboratory profile of measles cases with waning immunity with other measles cases. Polymerase chain reaction-positive (+) measles cases notified to Victoria's Department of Health and Human Services from 2008 to 2017 with immunoglobulin (Ig) M and IgG tested at diagnosis were classified according to serology at diagnosis: IgG negative (-) (nonimmune), IgM+/IgG+ (indeterminate), or IgM-/IgG+ (waning immunity). Between 2008 and 2017, 297 measles cases were notified, of whom 190 (64%) were included; 151 of 190 (79%) were nonimmune at diagnosis, 26 (14%) were indeterminate, and 13 (7%) had waning immunity. Between 2008-2013 and 2014-2017, the proportion of cases with waning immunity increased from 0 of 87 (0%) to 13 of 103 (13%) (P < .001) and the diagnostic sensitivity of initial IgM fell from 93% to 81% (P = .012), respectively. Seven (54%) waning immunity cases reported receiving measles-containing vaccines; 1 case had 2 documented doses. Compared with nonimmune and indeterminate cases, waning immunity cases were more likely to be male; less likely to report fever, coryza, and cough; and had lower burden of virus (higher cycle threshold values). Waning immunity cases had higher IgG titers than indeterminate cases (mean optical density values, 1.96 vs 0.71; P = .004). Onward transmission from 1 waning immunity case was documented. Waning immunity among measles cases, associated with secondary vaccine failure and modified clinical illness, is emerging in Victoria with transmission potential.

Evaluation of a new rapid fluorescence immunoassay for the diagnosis of dengue and Zika virus infection

BackgroundDengue (DENV) and Zika virus (ZIKV) are important mosquito-transmitted viruses. ObjectivesTo investigate the performance of Standard F, Fluorescence Immunoassay (FIA, SD Biosensor Inc., Suwon, South Korea) providing results in 15 min to detect DENV IgG, IgM and NS1Ag, and ZIKV IgG, IgM, and Ag. Study designA well-characterized panel of patient samples (11 acute DENV, 11 acute ZIKV, 10 past DENV, 10 past ZIKV infection, 36 with other conditions) were tested with the FIA test. ResultsIn acute DENV infection, the combination of FIA-NS1Ag and/or IgM positivity showed a sensitivity of 100%. In past DENV, FIA-IgG test showed a sensitivity of 70%. Specificity of FIA-DENV NS1Ag, IgG, and IgM was 87.5%, 83.5%, and 91.7%, respectively. The sensitivity of FIA-ZIKV IgM and FIA-ZIKV Ag, in confirmed acute infection, was 72.7% and 9.1%, respectively. FIA-ZIKV Ag did not improve the sensitivity in detecting acute ZIKV infection, being positive only in one IgM positive sample. In past ZIKV infection (32–183 days after symptom onset), FIA-ZIKV IgG and IgM showed a sensitivity of 40% and 80% respectively, generating an overall 90% sensitivity. Specificity of FIA-ZIKV Ag, IgM, and IgG was 92.6%, 100%, and 97%, respectively. ConclusionFIA test, a rapid and easy to perform assay, showed high sensitivity to detect acute DENV infection, but lower in acute ZIKV infection. In past ZIKV infections, the best performance of FIA test is obtained by combining detection of IgG and IgM.

Anti-Double-Stranded DNA Isotypes and Anti-C1q Antibody Improve the Diagnostic Specificity of Systemic Lupus Erythematosus.

Objectives We aimed to evaluate the value of immunoglobulin (Ig) G, IgM, and IgA isotypes of anti-double-stranded DNA (anti-dsDNA) and anti-C1q antibody in diagnosing systemic lupus erythematosus (SLE) patients and elucidate their association with disease activity and lupus nephritis. Methods Blood samples were obtained from 96 SLE patients, 62 other autoimmune disease patients, and 60 healthy blood donors. Anti-dsDNA IgG, IgM, and IgA isotypes and anti-C1q antibody were measured by enzyme-linked immunosorbent assay. Disease activity of SLE patients was assessed according to the SLE Disease Activity Index score. Results When specificity was greater than 90%, the sensitivity of anti-dsDNA IgG, IgM, and IgA isotypes and anti-C1q antibody in diagnosing SLE was 75%, 45%, 33%, and 49%, respectively. The prevalence of anti-dsDNA IgG (p = 0.002), anti-dsDNA IgA (p = 0.028), and anti-C1q antibody (p = 0.000) in active cases was significantly higher than those in inactive ones. In addition, the presence of anti-C1q antibody was associated with renal involvement (p = 0.032). Anti-dsDNA IgM showed no significant association with disease activity, but it was inversely linked with lupus nephritis (p = 0.005). When anti-dsDNA IgG and IgA and anti-C1q were combined to evaluate SLE disease activity, the specificity reached the highest level (90%). When anti-C1q positive was accompanied by anti-dsDNA IgM negative, the specificity of diagnosing lupus nephritis was up to 96%. Conclusions This study demonstrated the role of anti-dsDNA IgG, IgM, and IgA isotypes and anti-C1q antibody alone or combination in diagnosing SLE. Anti-dsDNA IgG and IgA and anti-C1q were shown to be associated with disease activity, while anti-dsDNA IgM and anti-C1q were associated with lupus nephritis. When the related antibodies were combined, the diagnostic specificity was significantly higher.