Diagnostic tests for hepatitis C: Recent trends in electrochemical immunosensor and genosensor analysis

Hepatitis C is a liver disease that is transmitted through contact with the blood of an infected person. An estimated 150 million individuals worldwide have been chronically infected with the hepatitis C virus(HCV). Hepatitis C shows significant genetic variation in the global population, due to the high rate of viral RNA mutation. There are six variants of the virus(HCV genotypes 1, 2, 3, 4, 5, and 6), with 15 recorded subtypes that vary in prevalence across different regions of the world. A variety of devices are used to diagnose hepatitis C, including HCV antibody test, HCV viral load test, HCV genotype test and liver biopsy. Rapid, inexpensive, sensitive, and robust analytical devices are therefore essential for effective diagnosis and monitoring of disease treatment. This review provides an overview of current electrochemical immunosensor and genosensortechnologies employed in HCV detection.There are a limited number of publications showing electrochemical biosensors being used for the detection of HCV.Due to their simplicity,specificity,and reliability,electrochemical biosensor devices have potential clinical applications in several viral infections.

Secondary analysis of malaria rapid diagnostic tests from rounds 5–8 of WHO product testing with a focus on false-negative results

Despite the widespread use of malaria rapid diagnostic test(RDT)in clinical practice,there are a lot of challenges.We conducted a secondary analysis of 129 malaria RDT data from rounds 5–8 of the World Health Organization(WHO)product testing summary and discuss the causes of false-negative(FN)results with a focus on low parasite density,improper RDT storage,operation and interpretation,and Plasmodium falciparum with a pfhrp2/3 gene deletion.The results demonstrated that the malaria RDTs currently commercially available might cause FN results in practice.

Could the Level in Parasitaemia of <i>Plasmodium</i>Determine Sensitivity to Various Diagnostic Tests?

The discovery of Plasmodium parasites and its incrimination as the principal cause of malaria in humans has continued to excite researchers towards inventing possible easier methods of diagnosing and identifying these pathological agents in order to mitigate, control and eliminate its continuous scourge to humanity. Currently, three diagnostic methods have been proposed, but agreements as to whether the level of parasitaemia in an individual could connote likely confirmations in the three methods i.e. gold standard, RDTs’ and PCR/NESTED PCR, have continued to be a subject of debate. To lay to rest the debate as reported in many studies, we collected blood samples from 100 symptomatic patients who reported to the Jos-Nigeria hospital and using the gold standard methods, we were able to confirm that 30 (30%) samples out of the 100 blood samples collected were positive to P. falciparum, chiefly recorded among duffy-negative Africans. Excited with our findings, we prepared the thick blood films for each sample and used it to estimate the levels of parasitaemia (parasites density) per μl of blood (i.e. 1+;2+;3+ and 4+) per 100 high power fields (|HPF). We then subjected the individually confirmed parasite density samples to the other two methods i.e. Rapid Diagnostic Test (one-step RTD and optimal-IT® RDT) and to molecular assay (PCR and the nested PCR). Interestingly, of the 30 positive samples, 18 (60%) were confirmed positive to the one-step and optimal-IT® RDTS, while 3 (30%) out of the 10 (100%) samples of various parasite density subjected to molecular assay (PCR and the nested PCR) were positive to only P. falciparum. Statistical analysis of variance based on single factor computed using SPSS indicates a no significant difference (P > 0.05) in the parasitaemia levels of the four groups/categories of patients;i.e. variance ratio of 0.011976 calculated was less than F-critical (2.816466) at 5% (0.05). Whereas gold standard could be considered as the optimal method, for the PCR/NESTED PCR, the sensitivity is dependent on high level of parasitaemia.

Assessment of Rapid Diagnostic Tests Algorithms in Transfusion Medicine Setting

Background: The rapid diagnostic tests play a pivotal role in the screening of viral markers in blood qualification for transfusion in limited resource setting. Therefore, it is important to assess their analytical performances to ensure their proper functioning. Material and Methods: We performed a cross- sectional study by successive recruitment to assess the diagnostic value of rapid diagnostic tests algorithms using ELISA as a reference test. A total of 661 blood from donors were enrolled for this study. Rapid Diagnostic Tests (RDTs) and ELISA tests were performed for each sample by a couple of double-blinded biotechnologists. Data were collected on case report form and captured in Microsoft Excel then the file was imported and analyzed using R software version 4.0.3. Results: The diagnostic accuracy for the algorithms are summarized in Table 1. For HIV-algorithm, the internal validity parameters were as follow: sensitivity (sens) 99.0% (95% CI = 97.8, 99.5);specificity (spec) 98.3% (95% CI = 90.9, 99.7);positive likelihood ratio (PLR) 57.4 (95% CI = 8.2, 401.0);negative likelihood ratio (NLR) 0.01 (95% CI = 0.0005, 0.02);diagnostic odd ratio (DOR) 4710. HBV-Ag/Ab RDTs achieve the following diagnostic accuracy: sens 99.7% (95% CI = 98.3, 99.9);spec 98.8% (95% CI = 96.9, 95.5);PLR 81.8 (95% CI = 30.9, 217.0);NLR 0.003 (95% CI = 0.0004, 0.02);DOR 14,110. The analytical performances of HCV-Ab RDTs were as follow: sens 98.7% (95% CI = 97.5, 99.4);spec 93.1% (95% CI = 78.0, 98.1);PLR 14.3 (95% CI = 3.8, 54.5);NLR 1.5 (95% CI = 0.8, 2.8);DOR 962.6. The parameters evaluating the external validity of RDTs screening for the three viral markers when the theorical prevalence was < 5% are summarized in Figure 3. At the prevalence < 5%, the NPV of the three RDTs were 99.96%, 99.99% and 99.94%. At the same prevalence, we found the following Positive Predictive Values (PPV) 70.82%, 77.59% and 37.35% for HIV-Ag/Ab RDTs, HBV-Ag RDTs and HCV-Ab RDTs algorithms, respectively. The overall areas under the received operating characteristic (ROC) curves were 98.6%, 99.2% and 99.2%;95.9% for HIV-Ag/Ab RDTs, HBV-Ag RDTs and HCV-Ab RDTs algorithms, respectively. Conclusion: RDTs algorithms can play a pivotal role in the screening of HIV-Ab/Ag, HBs-Ag in the setting of resources limited-countries where financial and technical expertise shortages are a standard fare. However, their use for diagnostic purposes must be done with great caution and the result must necessarily be confirmed with an ELISA or molecular technique particularly for HCV-RDTs algorithm which achieved an NLR value > 0.1.

Malaria rapid diagnostic tests in community pharmacies in Rwanda:availability,knowledge of community pharmacists,advantages,and disadvantages of licensing their use

Background Presumptive treatment of malaria is often practiced in community pharmacies across sub-Saharan Africa(SSA).To address this issue,the World Health Organization(WHO)recommends that malaria Rapid Diagnostic Tests(m-RDTs)be used in these settings,as they are used in the public sector.However,their use remains unlicensed in the community pharmacies in Rwanda.This can lessen their availability and foster presumptive treatment.Therefore,this study investigated the availability of m-RDTs,knowledge of community pharmacists on the use of m-RDTs,and explored Pharmacists’perceptions of the advantages and disadvantages of licensing the use of m-RDTs in community pharmacies.Methods This was a cross-sectional study among 200 licensed community pharmacists who were purposefully sampled nationwide from 11th February to 12th April 2022.Data was collected using an online data collection instrument composed of open-ended and closed-ended questions.Statistical analyses were performed using the Statistical Package for the Social Sciences(SPSS)version 25.0.The chi-square test was used to evaluate the association between the availability of m-RDTs and independent variables of interest.Content analysis was used for qualitative data.Results Although 59%were consulted by clients requesting to purchase m-RDTs,only 27%of the participants had m-RDTs in stock,66.5%had no training on the use of m-RDTs,and 18.5%were not at all familiar with using the m-RDTs.Most of the participants(91.5%)agreed that licensing the use of m-RDTs in community pharmacies could promote the rational use of antimalarials.The chi-square test indicated that being requested to sell m-RDTs(x^(2)=6.95,p=0.008),being requested to perform m-RDTs(x^(2)=5.39,p=0.02),familiarity using m-RDTs(x^(2)=17.24,p=0.002),availability of a nurse in the Pharmacy(x^(2)=11.68,p<0.001),and location of the pharmacy(x^(2)=9.13,p=0.048)were all significantly associated with the availability of m-RDTs in the pharmacy.Conclusions The availability of m-RDTs remains low in community pharmacies in Rwanda,and less training is provided to community pharmacists regarding the use of m-RDTs.Nevertheless,community pharmacists had positive perceptions of the advantages of licensing the use of m-RDTs.Thus,licensing the use of m-RDTs is believed to be the first step toward promoting the rational use of antimalarial medicines in Rwanda.

Evaluating the implementation of rapid diagnostic tests in a malaria elimination setting

Background It was recommended that malaria rapid diagnostic tests(RDTs)should be available in all epidemiological situations.But evidence was limited on the implementation of RDTs and its effectiveness in malaria elimination settings.This study examined the implementation of RDTs and how it affected the diagnosis of imported malaria patients in Jiangsu Province,China.Methods To scale up RDTs,this study developed an intervention package with four major elements covering the supply of RDT test,the training on RDTs,the monitoring and management of RDT use,and the advocacy of RDTs.By using a pretest-posttest control group design,we implemented the interventions in 4 cities in Jiangsu Province with the rest nine cities as controlled areas,from January 2017 to January 2018.Difference-in-Difference approach was used to evaluate the impact of the scale-up of RDTs on the identification of malaria cases.Three binary outcome measures were included to indicate delayed malaria diagnosis,malaria cases with confirmed malaria diagnosis at township-level institutions,and severe malaria cases,respectively.Linear probability regression was performed with time and group fixed effects and the interaction term between time and group.Results Intervention areas received sufficient RDT test supply,regular professional training programs,monthly tracking and management of RDT supply and use,and health education to targeted population.The implementation of interventions was associated with 10.8%(P=0.021)fewer patients with delayed diagnosis.But intervention areas did not see a higher likelihood of having confirmed diagnosis from township-level institutions(coefficient=-0.038,P=0.185)or reduced severe malaria cases(coef.=0.040,P=0.592).Conclusions The comprehensive package of RDT implementation in this study is promising in scaling up RDT use and improving access to care among malaria patients,especially in malaria elimination settings.

Knowledge about non-invasive diagnostic tests for varices in liver cirrhosis:A questionnaire survey to the Gastroenterology Branch of the Liaoning Medical Association,China

Background and aims:Due to the invasiveness of upper gastrointestinal endoscopy,non-invasive diagnostic tests for varices in liver cirrhosis have been widely established by numerous studies.A questionnaire survey,which was aimed at understanding the current knowledge about non-invasive diagnostic tests for varices in liver cirrhosis,was distributed among the members of Gastroenterology Branch of the Liaoning Medical Association.Methods:A questionnaire assessing the knowledge about non-invasive diagnostic tests for varices was sent to 42 members who participated in the entire ninth committee.They were from 33 hospitals in 13 cities of Liaoning Province,China.Results:Overall,97.6%(41/42)of participants responded to the questionnaire.A majority of participants were chief physicians(85.4%),had>20 years of experience in clinical work of digestive diseases(80.5%)and worked at tertiary hospitals(97.6%).In 46.3%of participants’departments,there were>200 patients with liver cirrhosis and gastroesophageal varices admitted every year.In 90.2%of participants’departments,upper gastrointestinal endoscopy was regularly employed for the diagnosis of gastroesophageal varices.Only six(15%)participants often used non-invasive diagnostic tests for varices in clinical practice.Thirty(75%)participants knew at least one non-invasive diagnostic test for varices.The knowledge of at least one non-invasive diagnostic test was significantly associated with the number of cirrhotic patients with varices(P¼0.038)or the regular use of gastrointestinal endoscopy to diagnose varices(P¼0.022).Conclusions:This questionnaire survey suggested that non-invasive diagnostic tests for varices in liver cirrhosis were rarely or never used in clinical practices in Liaoning Province,China.Reliable,non-invasive indexes should be further explored in a well-designed multi-center observational study.

Accuracy of three diagnostic tests used alone and in combination for detecting Helicobacter pylori infection in patients with bleeding gastric ulcers

Objective Accuracy of diagnostic methods for detecting Helicobacter pylori (H. pylori) infection among patients with bleeding peptic ulcers has not been thoroughly investigated. The aim of this study was to compare the diagnostic tests and their combined usage in detection of H. pylori infection in patients with bleeding gastric ulcers and without the use of nonsteroidal anti-inflammatory drugs.Methods A total of 57 patients who presented with bleeding gastric ulcers by endoscopy were enrolled. The status of H. pylori was identified by performing the rapid urease test (RUT), histology and 13C-labeled urea breath test (UBT). The criteria for having H. pylori infection was a minimum of two positive tests.Results The prevalence of H. pylori infection in our patient group was 80.7%. Among the three tests used: RUT, histology, and UBT, sensitivities were 56.5%, 97.8% and 100%, while specificities were 100%, 45.5% and 81.8%, respectively. The overall accuracies of the tests were 78.3%, 71.6% and 90.9%, respectively. Although UBT obtained significantly higher accuracy than histology (P=0.02) as opposed to RUT (P=0.11), UBT had significantly higher sensitivity than RUT (P<0.001). In terms of combining any two of the three tests, more accuracy (98.9%) was achieved when both UBT and histology were used to confirm the diagnosis of the other. Conversely, failure to use combined tests generated the potential of missing a proper H. pylori diagnosis.Conclusions UBT is superior to the other two tests in bleeding gastric ulcers. RUT lacks sensitivity for detection of H. pylori infection. However, the concomitant use of UBT and histology seems to be more accurate when gastric ulcers present with bleeding.

Cost-effectiveness analysis of malaria rapid diagnostic tests:a systematic review

Background:Rapid diagnostic tests(RDT)can effectively manage malaria cases and reduce excess costs brought by misdiagnosis.However,few studies have evaluated the economic value of this technology.The purpose of this study is to systematically review the economic value of RDT in malaria diagnosis.Main text:A detailed search strategy was developed to identify published economic evaluations that provide evidence regarding the cost-effectiveness of malaria RDT.Electronic databases including MEDLINE,EMBASE,Biosis Previews,Web of Science and Cochrane Library were searched from Jan 2007 to July 2018.Two researchers screened studies independently based on pre-specified inclusion and exclusion criteria.The Consolidated Health Economic Evaluation Reporting Standards(CHEERS)checklist was applied to evaluate the quality of the studies.Then cost and effectiveness data were extracted and summarized in a narrative way.Fifteen economic evaluations of RDT compared to other diagnostic methods were identified.The overall quality of studies varied greatly but most of them were scored to be of high or moderate quality.Ten of the fifteen studies reported that RDT was likely to be a cost-effective approach compared to its comparisons,but the results could be influenced by the alternatives,study perspectives,malaria prevalence,and the types of RDT.Conclusions:Based on available evidence,RDT had the potential to be more cost-effective than either microscopy or presumptive diagnosis.Further research is also required to draw a more robust conclusion.

Performance of clinical signs and symptoms,rapid and reference laboratory diagnostic tests for diagnosis of human African trypanosomiasis by passive screening in Guinea:a prospective diagnostic accuracy study

Background Passive diagnosis of human African trypanosomiasis(HAT)at the health facility level is a major component of HAT control in Guinea.We examined which clinical signs and symptoms are associated with HAT,and assessed the performance of selected clinical presentations,of rapid diagnostic tests(RDT),and of reference laboratory tests on dried blood spots(DBS)for diagnosing HAT in Guinea.Method The study took place in 14 health facilities in Guinea,where 2345 clinical suspects were tested with RDTs(HAT Sero-K-Set,rHAT Sero-Strip,and SD Bioline HAT).Seropositives underwent parasitological examination(reference test)to confirm HAT and their DBS were tested in indirect enzyme-linked immunoassay(ELISA)/Trypanosoma brucei gambiense,trypanolysis,Loopamp Trypanosoma brucei Detection kit(LAMP)and m18S quantitative PCR(qPCR).Multivariable regression analysis assessed association of clinical presentation with HAT.Sensitivity,specificity,positive and negative predictive values of key clinical presentations,of the RDTs and of the DBS tests for HAT diagnosis were determined.Results The HAT prevalence,as confirmed parasitologically,was 2.0%(48/2345,95%CI:1.5–2.7%).Odds ratios(OR)for HAT were increased for participants with swollen lymph nodes(OR=96.7,95%CI:20.7–452.0),important weight loss(OR=20.4,95%CI:7.05–58.9),severe itching(OR=45.9,95%CI:7.3–288.7)or motor disorders(OR=4.5,95%CI:0.89–22.5).Presence of at least one of these clinical presentations was 75.6%(95%CI:73.8–77.4%)specific and 97.9%(95%CI:88.9–99.9%)sensitive for HAT.HAT Sero-K-Set,rHAT Sero-Strip,and SD Bioline HAT were respectively 97.5%(95%CI:96.8–98.1%),99.4%(95%CI:99.0–99.7%)and 97.9%(95%CI:97.2–98.4%)specific,and 100%(95%CI:92.5–100.0%),59.6%(95%CI:44.3–73.3%)and 93.8%(95%CI:82.8–98.7%)sensitive for HAT.The RDT’s positive and negative predictive values ranged from 45.2–66.7%and 99.2–100%respectively.All DBS tests had specificities≥92.9%.While LAMP and m18S qPCR sensitivities were below 50%,trypanolysis and ELISA/T.b.gambiense had sensitivities of 85.3%(95%CI:68.9–95.0%)and 67.6%(95%CI:49.5–82.6%).Conclusions Presence of swollen lymph nodes,important weight loss,severe itching or motor disorders are simple but accurate clinical criteria for HAT referral in HAT endemic areas in Guinea.Diagnostic performances of HAT Sero-K-Set and SD Bioline HAT are sufficient for referring positives to microscopy.Trypanolysis on DBS may discriminate HAT patients from false RDT positives.

Performance of three rapid diagnostic tests for the detection of Cryptosporidium spp.and Giardia duodenalis in children with severe acute malnutrition and diarrhoea

Background:There is significant need for accurate diagnostic tools for Cryptosporidium spp.and Qiordia duodenalis infections in resource limited countries where diarrhoeal disease caused by these parasites is often prevalent.The present study assessed the diagnostic performance of three commercially available rapid diagnostic tests(RDTs)based on faecal-antigen detection for Cryptosporidium spp.and/or G.duodenalis infections in stool samples of children admitted with severe acute malnutrition(SAM)and diarrhoea.An established multiplex PCR was used as reference test.Methods:Stool samples from children with SAM and diarrhoea enrolled in a randomized controlled trial(registered at clinicaltrials.gov/ct2/show/NCT02246296)in Malawi(n=175)and Kenya(n=120)between December 2014 and December 2015 were analysed by a multiplex PCR for the presence of Cryptosporidium sppv G.duodenalis or Entomoebo histolytica parasite DNA.Cryptosporidium-positive samples were species typed using restriction fragment length polymorphism analysis.A sub-sample of the stool specimens(n=236)was used for testing with three different RDTs.Diagnostic accuracy of the tests under evaluation was assessed using the results of PCR as reference standard using MedCalc software.Pearson Chi-square test and Fisher's exact test were used to determine(significant)difference between the number of cryptosporidiosis or giardiasis cases found by PCR in Malawi and Kenya.The overall diagnostic accuracy of each RDT was calculated by plotting a receiver operating characteristic(ROC)curve for each test and to determine the area under the curve(AUC)using SPSS8 software.Results:Prevalence of Cryptosporidium spp.by PCR was 20.0 and 21.7%in Malawi and Kenya respectively,mostly C.hominis.G.duodenalis prevalence was 23.4 and 5.8%in Malawi and Kenya respectively.E histolytica was not detected by PCR.RDT testing followed the same pattern of prevalence.RDT sensitivities ranged for cryptosporidiosis from 42.9 to 76.9%and for G.duodenalis from 48.2 to 85.7%.RDT specificities ranged from 88.4 to 100%for Cryptosporidium spp.and from 91.2 to 99.2%for G.duodenalis infections.Based on the estimated area under the curve(AUC)values,all tests under evaluation had an acceptable overall diagnostic accuracy(>0.7),with the exception of one RDT for Cryptosporidium spp.in Malawi.Conclusions:All three RDTs for Cryptosporidium spp.and Giardia duodenalis evaluated in this study have a moderate sensitivity,but sufficient specificity.The main value of the RDTs is within their rapidness and their usefulness as screening assays in surveys for diarrhoea.

Evaluation of urea breath test as a diagnostic tool for Helicobacter pylori infection in adult dyspeptic patients

In this editorial,we discuss the article in the World Journal of Gastroenterology.The article conducts a meta-analysis of the diagnostic accuracy of the urea breath test(UBT),a non-invasive method for detecting Helicobacter pylori(H.pylori)infection in humans.It is based on radionuclide-labeled urea.Various methods,both invasive and non-invasive,are available for diagnosing H.pylori infection,inclu-ding endoscopy with biopsy,serology for immunoglobulin titers,stool antigen analysis,and UBT.Several guidelines recommend UBTs as the primary choice for diagnosing H.pylori infection and for reexamining after eradication therapy.It is used to be the first choice non-invasive test due to their high accuracy,specificity,rapid results,and simplicity.Moreover,its performance remains unaffected by the distribution of H.pylori in the stomach,allowing a high flow of patients to be tested.Despite its widespread use,the performance characteristics of UBT have been inconsistently described and remain incompletely defined.There are two UBTs available with Food and Drug Administration approval:The 13C and 14C tests.Both tests are affordable and can provide real-time results.Physicians may prefer the 13C test because it is non-radioactive,compared to 14C which uses a radioactive isotope,especially in young children and pregnant women.Although there was heterogeneity among the studies regarding the diagnostic accuracy of both UBTs,13C-UBT consistently outperforms the 14C-UBT.This makes the 13C-UBT the preferred diagnostic approach.Furthermore,the provided findings of the meta-analysis emphasize the significance of precise considerations when choosing urea dosage,assessment timing,and measurement techniques for both the 13C-UBT and 14C-UBT,to enhance diagnostic precision.

Urea breath test for Helicobacter pylori infection in adult dyspeptic patients: A meta-analysis of diagnostic test accuracy

BACKGROUND Helicobacter pylori(H.pylori)infection has been well-established as a significant risk factor for several gastrointestinal disorders.The urea breath test(UBT)has emerged as a leading non-invasive method for detecting H.pylori.Despite numerous studies confirming its substantial accuracy,the reliability of UBT results is often compromised by inherent limitations.These findings underscore the need for a rigorous statistical synthesis to clarify and reconcile the diagnostic accuracy of the UBT for the diagnosis of H.pylori infection.AIM To determine and compare the diagnostic accuracy of 13C-UBT and 14C-UBT for H.pylori infection in adult patients with dyspepsia.METHODS We conducted an independent search of the PubMed/MEDLINE,EMBASE,and Cochrane Central databases until April 2022.Our search included diagnostic accuracy studies that evaluated at least one of the index tests(^(13)C-UBT or ^(14)C-UBT)against a reference standard.We used the QUADAS-2 tool to assess the methodo-logical quality of the studies.We utilized the bivariate random-effects model to calculate sensitivity,specificity,positive and negative test likelihood ratios(LR+and LR-),as well as the diagnostic odds ratio(DOR),and their 95%confidence intervals.We conducted subgroup analyses based on urea dosing,time after urea administration,and assessment technique.To investigate a possible threshold effect,we conducted Spearman correlation analysis,and we generated summary receiver operating characteristic(SROC)curves to assess heterogeneity.Finally,we visually inspected a funnel plot and used Egger’s test to evaluate publication bias.endorsing both as reliable diagnostic tools in clinical practice.CONCLUSION In summary,our study has demonstrated that ^(13)C-UBT has been found to outperform the ^(14)C-UBT,making it the preferred diagnostic approach.Additionally,our results emphasize the significance of carefully considering urea dosage,assessment timing,and measurement techniques for both tests to enhance diagnostic precision.Nevertheless,it is crucial for researchers and clinicians to evaluate the strengths and limitations of our findings before implementing them in practice.

Evaluation of a Rapid Diagnostic Test, Boson Biotech SARS CoV-2 Ag, for the Detection of SARS-CoV-2 in Gabon

1) Background: Rapid and acurate diagnostic testing for case identification, quarantine, and contact tracing is essential for managing the COVID 19 pandemic. Rapid antigen detection tests are available, however, it is important to evaluate their performances before use. We tested a rapid antigen detection of SARS-CoV-2, based on the immunochromatography (Boson Biotech SARS-CoV-2 Ag Test (Xiamen Boson Biotech Co., Ltd., China)) and the results were compared with the real time reverse transcriptase-Polymerase chain reaction (RT-PCR) (Gold standard) results;2) Methods: From November 2021 to December 2021, samples were collected from symptomatic patients and asymptomatic individuals referred for testing in a hospital during the second pandemic wave in Gabon. All these participants attending “CTA Angondjé”, a field hospital set up as part of the management of COVID-19 in Gabon. Two nasopharyngeal swabs were collected in all the patients, one for Ag test and the other for RT-PCR;3) Results: A total of 300 samples were collected from 189 symptomatic and 111 asymptomatic individuals. The sensitivity and specificity of the antigen test were 82.5% [95%CI 73.8 - 89.3] and 97.9 % [95%CI 92.2 - 98.2] respectively, and the diagnostic accuracy was 84.4% (95% CI: 79.8 - 88.3%). The antigen test was more likely to be positive for samples with RT-PCR Ct values ≤ 32, with a sensitivity of 89.8%;4) Conclusions: The Boson Biotech SARS-CoV-2 Ag Test has good sensitivity and can detect SARS-CoV-2 infection, especially among symptomatic individuals with low viral load. This test could be incorporated into efficient testing algorithms as an alternative to PCR to decrease diagnostic delays and curb viral transmission.

Comparison of the diagnostic value of four tests for superior labrum anterior and posterior lesions of the shoulde

To compare the diagnostic value of four signs for superior labrum anterior and posterior (SLAP) lesions of the shoulder.Methods The physical examination was performed randomly on 81 cases with abnormalities of the shoulder.There were four tests,including Kibler anterior sliding test,Liu crank test,O’Brien active compression test and Kim biceps load test Ⅱ.The arthroscopic examination were also performed.The result of the arthroscopic examination was considered as a golden standard,so that we could estimate the diagnosis value of the four tests according to the method of evaluation of diagnosis test on clinical epidemiology,their sensitivity,specificity,positive and negative predictive value,accuracy.Results There were 21 cases diagnosed as SLAP lesions by arthroscopy.The diagnosis value of Kim biceps load test Ⅱ was the highest among the four tests,in which 19 of true positive,59 of true negative,1 of false positive,only 2 of false negative cases;while the sensitivity was 90.48%,specificity was 98.33%,positive predictive value was 95.00%,negative predictive value was 96.72%,and accuracy was 96.30%.However the sensitivity,specificity,positive predicitive value,negative predictive vale and accuracy of Kibler anterior sliding test were 76.19%,96.67%,88.89%,92.06%,91.33%;and those of Liu crank test were 85.71%,93.33%,81.82%,94.92%,91.35%;those of O’Brien active compression test were 80.95%,91.66%,77.27%,93.22%,88.89%.Conclusion Kim Biceps load test Ⅱ may be the best for clinical diagnosis of SLAP lesions of the shoulder.9 refs,4 figs,2 tabs.

Diagnostic Utility of Interferon-Gamma Release Assay in Tuberculous Lymphadenitis

Objective The aim of this study was to evaluate the diagnostic performance of T-SPOT.TB for tuberculous lymphadenitis.Methods Suspected tuberculous lymphadenitis patients between September 2010 and September 2018 who had both peripheral blood T-SPOT.TB test and lymph node biopsy were retrospectively enrolled in this study.The cutoff value of T-SPOT.TB test for peripheral blood was set as 24 spot forming cell(SFC)/106 periphreral blood monocyte cell(PBMC)according to the instruction of testing kits.The gold standard for diagnosis of TBL was the combination of microbiology results,histopathology results and patient's response to anti-TB treatment.Diagnostic efficacy of T-SPOT.TB was evaluated,including sensitivity,specificity,accuracy,predictive values,and likelihood ratio.Results Among 91 patients who met the inclusion criteria,we excluded 8 cases with incomplete clinical information and 6 cases who lost to follow-up.According to the gold standard,there were 37 cases of true TBL(9 confirmed TBL and 28 probable TBL),30 cases of non-TBL,and 10 cases of clinically indeterminate diagnosis who were excluded from the final analyses.The T-SPOT.TB tests yielded 43 cases of positive response and 24 cases of negative response.The sensitivity,specificity,accuracy,positive predictive value(PPV),negative predictive value(NPV),positive likelihood ratio(PLR)and negative likelihood ratio(NLR)of peripheral blood T-SPOT.TB for diagnosing TBL were 89.2%,66.7%,79.1%,76.7%,83.3%,2.68 and 0.16,respectively.The number of SFCs of T-SPOT.TB in TBL patients[432(134-1264)/106 PBMCs]was higher than that in non-TBL patients[0(0-30)/106 PBMCs]with a significant difference(Z=-5.306,P<0.001).Conclusion T-SPOT.TB is a rapid and simple diagnostic test for TBL with a high sensitivity and negative predictive value.

Diagnostic and economic value of carcinoembryonic antigen,carbohydrate antigen 19-9,and carbohydrate antigen 72-4 in gastrointestinal cancers

BACKGROUND The diagnostic and economic value of carcinoembryonic antigen(CEA),carbohydrate antigen 19-9(CA19-9)and CA72-4 for gastrointestinal malignant tumors lacked evaluation in a larger scale.AIM To reassess the diagnostic and economic value of the three tumor biomarkers.METHODS A retrospective analysis of all 32857 subjects who underwent CEA,CA19-9,CA72-4,gastroscopy and colonoscopy from October 2006 to May 2018 was conducted.Then,we assessed the discrimination and clinical usefulness.Total cost,cost per capita and cost-effectiveness ratios were used to evaluate the economic value of two schemes(gastrointestinal endoscopy for all people without blood tests vs both gastroscopy and colonoscopy when blood tests were positive).RESULTS The analysis of 32857 subjects showed that CEA was a qualified biomarker for colorectal cancer(CRC),while the diagnostic efficiencies of CA72-4 were catastrophic for all gastrointestinal cancers(GICs).Regarding early diagnosis,only CEA could be used for early CRC.The combination of biomarkers didn’t greatly increase the area under the curve.The economic indicators of CEA were superior to those of CA19-9,CA72-4 and any combination.At the threshold of 1.8μg/L to 10.4μg/L,all four indicators of CEA were lower than those in the scheme that conducted gastrointestinal endoscopy only.Subgroup analysis implied that the health checkup of CEA for people above 65 years old was economically valuable.CONCLUSION CEA had qualified diagnostic value for CRC and superior economic value for GICs,especially for elderly health checkup subjects.CA72-4 was not suitable as a diagnostic biomarker.

Accuracy Evaluation of A Diagnostic Test by Detecting Outliers and Influential Observations

Logit regression analysis is widely applied in scientific studies and laboratory experiments, where skewed observations on a data set are often encountered. A number of problems with this method, for example, oudiers and influential observations, can cause overdispersion when a model is fitted. In this study a systematic statistical approach, including the plotting of several indices is used to diagnose the lack-of-fit of a logistic regression model. The outliers and influential observations on data from laboratory experiments are then detected. Specifically we take account of the interaction of an internal sohtary wave （ISW） with an obstacle, i.e., an underwater ridge, and also analyze the effects of the ridge height, the lower layer water depth, and the potential energy on the amplitude-based transmission rate of the ISW. As concluded, the goodness-of-fit of the revised logit regression model is better than that of the model without this approach.

Triple non-invasive diagnostic test for exclusion of common bile ducts stones before laparoscopic cholecystectomy

AIM: To evaluate the impact of a preoperative "triple non-invasive diagnostic test" for diagnosis and/or exclusion of common bile duct stones. METHODS: All patients with symptomatic gallstone disease, operated on by laparoscopic cholecystectomy from March 2004 to March 2006 were studied retrospectively. Two hundred patients were included and reviewed by using a triple diagnostic test including: patient's medical history, routine liver function tests and routine ultrasonography. All patients were followed up 2-24 mo after surgery to evaluate the impact of triple diagnostic test. RESULTS: Twenty-five patients were identified to have common bile duct stones. Lack of history of stones, negative laboratory tests and normal ultrasonography alone was proven to exclude common bile duct stones in some patients. However, a combination of these three components (triple diagnostic), was proven to be the most statistically significant test to exclude common bile duct stones in patients with gallstone disease. CONCLUSION: Using a combination of routinely used diagnostic components as triple diagnostic modality would increase the diagnostic accuracy of common bile duct stones preoperatively. This triple non-invasive test is recommended for excluding common bile duct stones and to identify patients in need for other investigations.

Multiparametric ultrasound as a new concept of assessment of liver tissue damage

Liver disease accounts for approximately 2 million deaths per year worldwide.All chronic liver diseases(CLDs),whether of toxic,genetic,autoimmune,or infectious origin,undergo typical histological changes in the structure of the tissue.These changes may include the accumulation of extracellular matrix material,fats,triglycerides,or tissue scarring.Noninvasive methods for diagnosing CLD,such as conventional B-mode ultrasound(US),play a significant role in diagnosis.Doppler US,when coupled with B-mode US,can be helpful in evaluating the hemodynamics of hepatic vessels and detecting US findings associated with hepatic decompensation.US elastography can assess liver stiffness,serving as a surrogate marker for liver fibrosis.It is important to note that interpreting these values should not rely solely on a histological classification.Contrast-enhanced US(CEUS)provides valuable information on tissue perfusion and enables excellent differentiation between benign and malignant focal liver lesions.Clinical evaluation,the etiology of liver disease,and the patient current comorbidities all influence the interpretation of liver stiffness measurements.These measurements are most clinically relevant when interpreted as a probability of compensated advanced CLD.B-mode US offers a subjective estimation of fatty infiltration and has limited sensitivity for mild steatosis.The controlled attenuation parameter requires a dedicated device,and cutoff values are not clearly defined.Quan-titative US parameters for liver fat estimation include the attenuation coefficient,backscatter coefficient,and speed of sound.These parameters offer the advantage of providing fat quantification alongside B-mode evaluation and other US parameters.Multiparametric US(MPUS)of the liver introduces a new concept for complete noninvasive diagnosis.It encourages examiners to utilize the latest features of an US machine,including conventional B-mode,liver stiffness evaluation,fat quantification,dispersion imaging,Doppler US,and CEUS for focal liver lesion characterization.This comprehensive approach allows for diagnosis in a single examination,providing clinicians worldwide with a broader perspective and becoming a cornerstone in their diagnostic arsenal.MPUS,in the hands of skilled clinicians,becomes an invaluable predictive tool for diagnosing,staging,and monitoring CLD.