scholarly journals Typhoid Fever Diagnosis in Endemic Countries: A Clog in the Wheel of Progress?

Medicina ◽  
2018 ◽  
Vol 54 (2) ◽  
pp. 23 ◽  
Author(s):  
Olumide Ajibola ◽  
Mari Mshelia ◽  
Bashar Gulumbe ◽  
Anthonius Eze
Keyword(s):  
Typhoid Fever ◽  
Sensitivity And Specificity ◽  
New Technologies ◽  
Point Of Care ◽  
Multidrug Resistant ◽  
Sub Saharan Africa ◽  
Surveillance Systems ◽  
Serological Tests ◽  
Laboratory Surveillance ◽  
Low Sensitivity

Typhoid fever causes significant morbidity and mortality in developing countries, with inaccurate estimates in some countries affected, especially those situated in Sub-Saharan Africa. Disease burden assessment is limited by lack of a high degree of sensitivity and specificity by many current rapid diagnostic tests. Some of the new technologies, such as PCR and proteomics, may also be useful but are difficult for low-resource settings to apply as point-of-care diagnostics. Weak laboratory surveillance systems may also contribute to the spread of multidrug resistant Salmonella serovar Typhi across endemic areas. In addition, most typhoid-endemic countries employ serological tests that have low sensitivity and specificity making diagnosis unreliable. Here we review currently available typhoid fever diagnostics, and advances in serodiagnosis of S. Typhi.

scholarly journals Diagnostic accuracy of serological tests for covid-19: systematic review and meta-analysis

BMJ ◽  
2020 ◽  
pp. m2516 ◽  
Author(s):  
Mayara Lisboa Bastos ◽  
Gamuchirai Tavaziva ◽  
Syed Kunal Abidi ◽  
Jonathon R Campbell ◽  
Louis-Patrick Haraoui ◽  
...  
Keyword(s):  
Systematic Review ◽  
Diagnostic Accuracy ◽  
Sensitivity And Specificity ◽  
Symptom Onset ◽  
Serological Test ◽  
Point Of Care ◽  
Meta Analysis ◽  
Risk Of Bias ◽  
Serological Tests ◽  
Immunoglobulin Class

AbstractObjectiveTo determine the diagnostic accuracy of serological tests for coronavirus disease-2019 (covid-19).DesignSystematic review and meta-analysis.Data sourcesMedline, bioRxiv, and medRxiv from 1 January to 30 April 2020, using subject headings or subheadings combined with text words for the concepts of covid-19 and serological tests for covid-19.Eligibility criteria and data analysisEligible studies measured sensitivity or specificity, or both of a covid-19 serological test compared with a reference standard of viral culture or reverse transcriptase polymerase chain reaction. Studies were excluded with fewer than five participants or samples. Risk of bias was assessed using quality assessment of diagnostic accuracy studies 2 (QUADAS-2). Pooled sensitivity and specificity were estimated using random effects bivariate meta-analyses.Main outcome measuresThe primary outcome was overall sensitivity and specificity, stratified by method of serological testing (enzyme linked immunosorbent assays (ELISAs), lateral flow immunoassays (LFIAs), or chemiluminescent immunoassays (CLIAs)) and immunoglobulin class (IgG, IgM, or both). Secondary outcomes were stratum specific sensitivity and specificity within subgroups defined by study or participant characteristics, including time since symptom onset.Results5016 references were identified and 40 studies included. 49 risk of bias assessments were carried out (one for each population and method evaluated). High risk of patient selection bias was found in 98% (48/49) of assessments and high or unclear risk of bias from performance or interpretation of the serological test in 73% (36/49). Only 10% (4/40) of studies included outpatients. Only two studies evaluated tests at the point of care. For each method of testing, pooled sensitivity and specificity were not associated with the immunoglobulin class measured. The pooled sensitivity of ELISAs measuring IgG or IgM was 84.3% (95% confidence interval 75.6% to 90.9%), of LFIAs was 66.0% (49.3% to 79.3%), and of CLIAs was 97.8% (46.2% to 100%). In all analyses, pooled sensitivity was lower for LFIAs, the potential point-of-care method. Pooled specificities ranged from 96.6% to 99.7%. Of the samples used for estimating specificity, 83% (10 465/12 547) were from populations tested before the epidemic or not suspected of having covid-19. Among LFIAs, pooled sensitivity of commercial kits (65.0%, 49.0% to 78.2%) was lower than that of non-commercial tests (88.2%, 83.6% to 91.3%). Heterogeneity was seen in all analyses. Sensitivity was higher at least three weeks after symptom onset (ranging from 69.9% to 98.9%) compared with within the first week (from 13.4% to 50.3%).ConclusionHigher quality clinical studies assessing the diagnostic accuracy of serological tests for covid-19 are urgently needed. Currently, available evidence does not support the continued use of existing point-of-care serological tests.Study registrationPROSPERO CRD42020179452.

scholarly journals Performance of SARS-CoV-2 Serology tests: Are they good enough?

2020 ◽  
Author(s):  
Isabelle Piec ◽  
Emma English ◽  
M Annette Thomas ◽  
Samir Dervisevic ◽  
William D Fraser ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Respiratory Infections ◽  
Point Of Care ◽  
False Negative ◽  
Rapid Test ◽  
Diagnostic Sensitivity ◽  
Medical Community ◽  
Antibody Detection ◽  
Serological Tests ◽  
Negative Results

AbstractBackgroundIn the emergency of the SARS-CoV-2 pandemic, great efforts were made to quickly provide serology testing to the medical community however, these methods have been introduced into clinical practice without the complete validation usually required by the regulatory organizations.MethodsSARS-CoV-2 patient samples (n=43) were analysed alongside pre-pandemic control specimen (n=50), confirmed respiratory infections (n=50), inflammatory polyarthritis (n=22) and positive for thyroid stimulating immunoglobulin (n=30). Imprecision, diagnostic sensitivity and specificity and concordance were evaluated on IgG serologic assays from EuroImmun, Epitope Diagnostics (EDI), Abbott Diagnostics and DiaSorin and a rapid IgG/IgM test from Healgen.ResultsEDI and EuroImmun imprecision was 0.02-14.0% CV. Abbott and DiaSorin imprecision (CV) ranged from 5.2% - 8.1% and 8.2% - 9.6% respectively. Diagnostic sensitivity of the assays were 100% (CI: 80-100%) for Abbott, EDI and EuroImmun and 95% (CI: 73-100%) for DiaSorin at ≥14 days post PCR. Only the Abbott assay had a diagnostic specificity of 100% (CI: 91-100%). EuroImmun cross-reacted in 3 non-SARS-CoV-2 respiratory infections and 2 controls. The DiaSorin displayed more false negative results and cross-reacted in six cases across all conditions tested. EDI had one cross-reactive sample. The Healgen rapid test showed excellent sensitivity and specificity. Overall, concordance of the assays ranged from 76.1% to 97.9%.ConclusionsSerological tests for SARS-CoV-2 showed good analytical performance. The head-to-head analysis of samples revealed differences in results that may be linked to the use of nucleocapsid or spike proteins. The point of care device tested demonstrated adequate performance for antibody detection.

scholarly journals Seroprevalence of anti-SARS-CoV-2 IgG antibodies in Juba, South Sudan: a population-based study

2021 ◽  
Author(s):  
Kirsten E. Wiens ◽  
Pinyi Nyimol Mawien ◽  
John Rumunu ◽  
Damien Slater ◽  
Forrest K. Jones ◽  
...  
Keyword(s):  
Test Performance ◽  
Serological Test ◽  
South Sudan ◽  
Bayesian Regression ◽  
Sub Saharan Africa ◽  
Surveillance Systems ◽  
Igg Antibody ◽  
Serological Tests ◽  
Cross Sectional ◽  
Sub Saharan

AbstractBackgroundRelatively few COVID-19 cases and deaths have been reported through much of sub-Saharan Africa, including South Sudan, although the extent of SARS-CoV-2 spread remains unclear due to weak surveillance systems and few population-representative serosurveys.MethodsWe conducted a representative household-based cross-sectional serosurvey in Juba, South Sudan. We quantified IgG antibody responses to SARS-CoV-2 spike protein receptor-binding domain and estimated seroprevalence using a Bayesian regression model accounting for test performance.ResultsWe recruited 2,214 participants from August 10 to September 11, 2020 and 22.3% had anti-SARS-CoV-2 IgG titers above levels in pre-pandemic samples. After accounting for waning antibody levels, age, and sex, we estimated that 38.5% (32.1 - 46.8) of the population had been infected with SARS-CoV-2. For each RT-PCR confirmed COVID-19 case, 104 (87-126) infections were unreported. Background antibody reactivity was higher in pre-pandemic samples from Juba compared to Boston, where the serological test was validated. The estimated proportion of the population infected ranged from 30.1% to 60.6% depending on assumptions about test performance and prevalence of clinically severe infections.ConclusionsSARS-CoV-2 has spread extensively within Juba. Validation of serological tests in sub-Saharan African populations is critical to improve our ability to use serosurveillance to understand and mitigate transmission.

The utility of point-of-care urine trypsinogen dipstick test for diagnosing acute pancreatitis in an emergency unit

2021 ◽  
Author(s):  
Amar Simha ◽  
Atul Saroch ◽  
Ashok K Pannu ◽  
Deba P Dhibar ◽  
Navneet Sharma ◽  
...  
Keyword(s):  
Acute Pancreatitis ◽  
Abdominal Pain ◽  
Diagnostic Accuracy ◽  
Diagnostic Test ◽  
Sensitivity And Specificity ◽  
Pain Sensitivity ◽  
Point Of Care ◽  
Emergency Unit ◽  
Dipstick Test ◽  
Low Sensitivity

Background: A point-of-care diagnostic test for acute pancreatitis could help in early triage and management of this condition. Materials & methods: Urine trypsinogen dipstick test (UTDT) was performed in consecutive cases suspected to have acute pancreatitis and diagnostic accuracy calculated. Results: Of 187 patients, 90 were have acute pancreatitis and UTDT was positive in 61 (67.7%). In the 97 non pancreatitis cases, UTDT was positive in nine (9.3%). The sensitivity and specificity of UTDT for acute pancreatitis was 67.8% and 90.7%, respectively. In patients presenting within 3 days of abdominal pain, sensitivity and specificity were 72.7% and 91.8%, respectively. Discussion: While offering the possibility of a point of care diagnosis, the low sensitivity of UTDT could be a concern with its routine use.

scholarly journals New Challenges in Malaria Elimination

2021 ◽  
Author(s):  
Susanta Kumar Ghosh ◽  
Chaitali Ghosh
Keyword(s):  
Malaria Elimination ◽  
New Technologies ◽  
Point Of Care ◽  
Artemisinin Resistance ◽  
Sub Saharan Africa ◽  
Chloroquine Resistance ◽  
World Health ◽  
Synthetic Pyrethroids ◽  
Sub Saharan ◽  
Health Organization

In recent years, efforts to eliminate malaria has gained a tremendous momentum, and many countries have achieved this goal — but it has faced many challenges. Recent COVID-19 pandemic has compounded the challenges due to cessation of many on-field operations. Accordingly, the World Health Organization (WHO) has advocated to all malaria-endemic countries to continue the malaria elimination operations following the renewed protocols. The recent reports of artemisinin resistance in Plasmodium falciparum followed by indication of chloroquine resistance in P. vivax, and reduced susceptibility of synthetic pyrethroids used in long lasting insecticide nets are some issues hindering the elimination efforts. Moreover, long distance night migration of vector mosquitoes in sub-Saharan Africa and invasion of Asian vector Anopheles stephensi in many countries including Africa and Southeast Asia have added to the problems. In addition, deletion of histidine rich protein 2 and 3 (Pfhrp2/3) genes in P. falciparum in many countries has opened new vistas to be addressed for point-of-care diagnosis of this parasite. It is needed to revisit the strategies adopted by those countries have made malaria elimination possible even in difficult situations. Strengthening surveillance and larval source management are the main strategies for successful elimination of malaria. New technologies like Aptamar, and artificial intelligence and machine learning would prove very useful in addressing many ongoing issues related to malaria elimination.

scholarly journals Serological determinants of COVID-19

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Annalisa Noce ◽  
Maria Luisa Santoro ◽  
Giulia Marrone ◽  
Cartesio D’Agostini ◽  
Ivano Amelio ◽  
...  
Keyword(s):  
Gold Standard ◽  
Point Of Care ◽  
Standard Test ◽  
Serological Tests ◽  
Point Of Care Test ◽  
Global Pandemic ◽  
Chemiluminescent Immunoassay ◽  
Low Sensitivity ◽  
Short Time

Abstract Background Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection spreaded rapidly worldwide, as far as it has become a global pandemic. Therefore, the introduction of serological tests for determination of IgM and IgG antibodies has become the main diagnostic tool, useful for tracking the spread of the virus and for consequently allowing its containment. In our study we compared point of care test (POCT) lateral flow immunoassay (FIA) vs automated chemiluminescent immunoassay (CLIA), in order to assess their specificity and sensibility for COVID-19 antibodies detection. Results We find that different specificities and sensitivities for IgM and IgG tests. Notably IgM POCT FIA method vs CLIA method (gold standard) has a low sensitivity (0.526), while IgG POCT FIA method vs CLIA method (gold standard) test has a much higher sensitivity (0.937); further, with respect of IgG, FIA and CLIA could arguably provide equivalent information. Conclusions FIA method could be helpful in assessing in short time, the possible contagiousness of subjects that for work reasons cannot guarantee “social distancing”.

scholarly journals Serological Determinants of COVID-19

2020 ◽  
Author(s):  
Annalisa Noce ◽  
Maria Luisa Santoro ◽  
Giulia Marrone ◽  
Cartesio D’Agostini ◽  
Ivano Amelio ◽  
...  
Keyword(s):  
Gold Standard ◽  
Point Of Care ◽  
Standard Test ◽  
Serological Tests ◽  
Point Of Care Test ◽  
Global Pandemic ◽  
Chemiluminescent Immunoassay ◽  
Low Sensitivity ◽  
Short Time

Abstract Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection spreaded rapidly worldwide, as far as it has become a global pandemic. Therefore, the introduction of serological tests useful for the determination of IgM and IgG antibodies, it has become the main diagnostic tool, useful for tracking the spread of the virus and consequently its containment. In our study we compared point of care test (POCT) lateral flow immunoassay (FIA) vs automated chemiluminescent immunoassay (CLIA), in order to assess their specificity and sensibility against COVID-19 antibodies detection. Results: We find that different specificities and sensitivities for IgG and IgM tests. Notably IgM POCT FIA method vs CLIA method (gold standard) has a low sensitivity (0.526), while POCT FIA method vs CLIA method (gold standard) test has a much higher sensitivity (0.937); further, with respect of IgG, FIA and CLIA could arguably provide the same information. Conclusions: FIA method could be helpful in assessing in short time, the possible contagiousness of subjects that for work reasons cannot guarantee “social distancing”.

scholarly journals Recent Advances in the Evaluation of Serological Assays for the Diagnosis of SARS-CoV-2 Infection and COVID-19

2021 ◽  
Vol 8 ◽  
Author(s):  
Angela Chiereghin ◽  
Rocco Maurizio Zagari ◽  
Silvia Galli ◽  
Alessandra Moroni ◽  
Liliana Gabrielli ◽  
...  
Keyword(s):  
Point Of Care ◽  
Standard Test ◽  
Enzyme Linked Immunosorbent Assay ◽  
Nasopharyngeal Swab ◽  
Pcr Assay ◽  
Serological Tests ◽  
Retrospective Diagnosis ◽  
Specific Igg ◽  
Low Sensitivity ◽  
Few Data

Introduction: Few data on the diagnostic performance of serological tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection are currently available. We evaluated sensitivity and specificity of five different widely used commercial serological assays for the detection of SARS-CoV-2–specific IgG, IgM, and IgA antibodies using reverse transcriptase-PCR assay in nasopharyngeal swab as reference standard test.Methods: A total of 337 plasma samples collected in the period April–June 2020 from SARS-CoV-2 RT-PCR positive (n = 207) and negative (n = 130) subjects were investigated by one point-of-care lateral flow immunochromatographic assay (LFIA IgG and IgM, Technogenetics) and four fully automated assays: two chemiluminescence immunoassays (CLIA-iFlash IgG and IgM, Shenzhen YHLO Biotech and CLIA-LIAISON® XL IgG, DiaSorin), one electrochemiluminescence immunoassay (ECLIA-Elecsys® total predominant IgG, Roche), and one enzyme-linked immunosorbent assay (ELISA IgA, Euroimmune).Results: The overall sensitivity of all IgG serological assays was >80% and the specificity was >97%. The sensitivity of IgG assays was lower within 2 weeks from the onset of symptoms ranging from 70.8 to 80%. The LFIA and CLIA-iFlash IgM showed an overall low sensitivity of 47.6 and 54.6%, while the specificity was 98.5 and 96.2%, respectively. The ELISA IgA yielded a sensitivity of 84.3% and specificity of 81.7%. However, the ELISA IgA result was indeterminate in 11.7% of cases.Conclusions: IgG serological assays seem to be a reliable tool for the retrospective diagnosis of SARS-CoV-2 infection. IgM assays seem to have a low sensitivity and IgA assay is limited by a substantial rate of indeterminate results.

scholarly journals Diagnostic Accuracy of HemotypeSC as a Point-of-Care Testing Device for Sickle Cell Disease: Findings from a Southwestern State in Nigeria and Implications for Patient Care in Resource-Poor Settings of sub-Saharan Africa

2021 ◽  
Vol 8 ◽  
pp. 2333794X2110167
Author(s):  
Oladele S. Olatunya ◽  
Dulcinea M. Albuquerque ◽  
Adeniyi F. Fagbamigbe ◽  
Opeyemi A. Faboya ◽  
Ayotunde E. Ajibola ◽  
...  
Keyword(s):  
Sickle Cell Disease ◽  
Sensitivity And Specificity ◽  
Sickle Cell ◽  
Point Of Care ◽  
Sub Saharan Africa ◽  
Testing Device ◽  
Cell Disease ◽  
Point Of Care Testing ◽  
Predictive Values ◽  
Sub Saharan

This study aimed to determine the performance of a rapid, point-of-care testing device (HemotypeSC)™ for diagnosing sickle cell disease (SCD) relative to 2 commonly-used methods compared to DNA polymerase chain reaction (PCR) as the reference standard. The diagnostic performance of (HemotypeSC)™ in diagnosing SCD and determining various other Hb genotypes relative to high performance liquid chromatography (HPLC) and cellulose acetate Hb electrophoresis in alkaline buffer (CAE) was investigated among 156 participants aged 4 to 23 years in Ekiti, Southwest Nigeria. PCR was considered as the reference method/gold standard. The sensitivity and specificity for SS, SC, AS, AC, and AA genotypes by HemotypeSC and HPLC when compared with PCR, were each 100%. Similarly, their positive and negative predictive values were each 100%. However, sensitivity and specificity for identifying these Hb genotypes by CAE were 100, 100, 96.5, 0, 99.2%, and 99, 100, 92.9, 0, 91.7%. Also, CAE did not identify any of the 2 HbAC individuals that were correctly identified by PCR and both HemotypeSC, and HPLC, thus representing 100% HbAC misdiagnosis. In conclusion, this study shows that HemotypeSC has perfect concordance with PCR and 100% accuracy in diagnosing SCD in the population tested. Its ease of use, accuracy and other attributes make it suitable for use in sub-Saharan Africa for rapid determination of Hb genotypes.

scholarly journals Performance of SARS-CoV-2 serology tests: Are they good enough?

PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0245914
Author(s):  
Isabelle Piec ◽  
Emma English ◽  
Mary Annette Thomas ◽  
Samir Dervisevic ◽  
William D. Fraser ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Respiratory Infections ◽  
Point Of Care ◽  
False Negative ◽  
Rapid Test ◽  
Diagnostic Sensitivity ◽  
Medical Community ◽  
Antibody Detection ◽  
Serological Tests ◽  
Negative Results

In the emergency of the SARS-CoV-2 pandemic, great efforts were made to quickly provide serology testing to the medical community however, these methods have been introduced into clinical practice without the complete validation usually required by the regulatory organizations. SARS-CoV-2 patient samples (n = 43) were analyzed alongside pre-pandemic control specimen (n = 50), confirmed respiratory infections (n = 50), inflammatory polyarthritis (n = 22) and positive for thyroid stimulating immunoglobulin (n = 30). Imprecision, diagnostic sensitivity and specificity and concordance were evaluated on IgG serologic assays from EuroImmun, Epitope Diagnostics (EDI), Abbott Diagnostics and DiaSorin and a rapid IgG/IgM test from Healgen. EDI and EuroImmun imprecision was 0.02–14.0% CV. Abbott and DiaSorin imprecision (CV) ranged from 5.2%–8.1% and 8.2%–9.6% respectively. Diagnostic sensitivity of the assays was 100% (CI: 80–100%) for Abbott, EDI and EuroImmun and 95% (CI: 73–100%) for DiaSorin at ≥14 days post PCR. Only the Abbott assay had a diagnostic specificity of 100% (CI: 91–100%). EuroImmun cross-reacted in 3 non-SARS-CoV-2 respiratory infections and 2 controls. The DiaSorin displayed more false negative results and cross-reacted in six cases across all conditions tested. EDI had one cross-reactive sample. The Healgen rapid test showed excellent sensitivity and specificity. Overall, concordance of the assays ranged from 76.1% to 97.9%. Serological tests for SARS-CoV-2 showed good analytical performance. The head-to-head analysis of samples revealed differences in results that may be linked to the use of nucleocapsid or spike proteins. The point of care device tested demonstrated adequate performance for antibody detection.

Sign in / Sign up

Export Citation Format

Share Document