Performance Of Rapid Test Research Articles

Impact of animal saliva on the performance of rapid antigen tests for detection of SARS-CoV-2 (wildtype and variants B.1.1.7 and B.1.351)

SARS-CoV-2 infects several animal species and SARS-CoV-2 variants of concern (VOCs) may even show (as in humans) enhanced inter- and intra-species transmission rates. We correlated sensitivity data of SARS-CoV-2 rapid antigen tests (RATs) to viral RNA genome equivalents analyzed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Further, we checked their suitability for testing animals by assessing saliva and VOC effects. Viral loads up to 2 logs (RNA copy number) under the hypothetical SARS-CoV-2 infectivity threshold were detected by most analyzed RATs. However, while saliva from various animal species showed generally no adverse effects on the RATs’ analytical sensitivities, the detection of VOCs B.1.1.7 and B.1.351 was in some RATs inferior to non-VOC viruses.

Validation of an At-Home Direct Antigen Rapid Test for COVID-19

This cohort study examines the performance of direct antigen rapid tests compared with that of quantitative real-time polymerase chain reaction for analyzing self-collected nasal specimens for the presence of SARS-CoV-2.

"The effectiveness of rapid antigen test-based for SARS-CoV-2 detection in nursing homes in Valencia, Spain".

The usefulness of the PANBIO ™ COVID-19 Ag rapid test for SARS-CoV-2 infection detection has not been widely studied, especially in specific population groups such as the elderly who are institutionalized. Rapid diagnostic tests have the potential to benefit testing strategies, as they have short turnaround times, they are cheap, simple to perform and can be used in decentralized testing. The objective of this study is to show the performance of the PANBIO™ COVID-19 Ag Rapid test device conducted at geriatric institutions and to compare results to those obtained from RT-PCR. A total of 448 individuals were enrolled in the study, including both residents and employees. Nasopharyngeal swabs were collected for both PANBIO™ COVID-19 Ag Rapid test and RT-PCR testing. All the samples were analyzed by specialized microbiologists. A total of 117 out of 448 individuals (26%) tested positive by RT-PCR, of whom 99 (85%) returned positive Antigen test results. There were 18 Antigen negative cases with positive RT-PCR results. Accordingly, concordance between RT-PCR and Antigen test results was acceptable (K index, 0.89; 95% IC 0.8455–0.9345). Overall sensitivity and specificity of Antigen test was 85% and 100%, respectively. When defining RT-PCR CT positivity on a cut-off value of 35, LFA sensitivity was 90%. In case a cut-off value of 30 was used, LFA would increase up to 99%. In this real-life evaluation of the PANBIO™ COVID-Ag rapid test, the assay reliably identified SARS-CoV-2 infected individuals with low CT-values by RT-PCR. False negative results were observed only at high CT-values, meaning low viral loads in nasopharyngeal samples.

Diagnostic Properties of Three SARS-CoV-2 Antibody Tests.

Serological assays emerged as complementary tools to RT-PCR in the diagnosis of SARS-CoV-2 as well as being needed for epidemiological studies. This study aimed to assess the performance of a rapid test (RT) compared to that of serological tests using finger prick blood samples. A total of 183 samples were evaluated, 88 of which were collected from individuals with negative RT-PCR and 95 from positive RT-PCR individuals. The diagnostic performance of RT (WONDFO®) and LUMIT (PROMEGA®) were compared to that of ELISA (EUROIMMUN®) for detecting antibodies against SARS-CoV-2 according to time from symptoms onset. The IgG antibody tests were detected in 77.4% (LUMIT), 77.9% (RT), and 80.0% (ELISA) of individuals. The detection of antibodies against SARS-CoV-2 increases in accordance with increasing time from symptoms onset. Considering only time from symptoms onset >21 days, the positivity rate ranged from 81.8 to 97.0% between the three tests. The RT and LUMIT showed high agreement with ELISA (agreement = 91.5%, k = 0.83, and agreement = 96.3%, k = 0.9, respectively) in individuals who had symptoms 15 to 21 days before sample collection. Compared to that of the ELISA assay, our results show sensitivity ranged from 95% to 100% for IgG antibody detection in individuals with symptoms onset between 15 and 21 days before sample collection. The specificity was 100% in individuals with symptoms onset >15 days before serological tests. This study shows good performance and high level of agreement of three immunoassays for the detection of SARS-CoV-2 antibodies.

Time scale performance of rapid antigen testing for SARS-CoV-2: Evaluation of 10 rapid antigen assays.

There is a great demand for more rapid tests for SARS‐CoV‐2 detection to reduce waiting time, boost public health strategies for combating disease, decrease costs, and prevent overwhelming laboratory capacities. This study was conducted to assess the performance of 10 lateral flow device viral antigen immunoassays for the detection of SARS‐CoV‐2 in nasopharyngeal swab specimens. We analyzed 231 nasopharyngeal samples collected from October 2020 to December 2020, from suspected COVID‐19 cases and contacts of positive cases at Biotechnology Research Center laboratories, Tripoli, Libya. The performance of 10 COVID‐19 Antigen (Ag) rapid test devices for the detection of SARS‐CoV‐2 antigen was compared to a quantitative reverse transcription‐polymerase chain reaction (RT‐qPCR). In this study, 161 cases had symptoms consistent with COVID‐19. The mean duration from symptom onset was 6.6 ± 4.3 days. The median cycle threshold (C t) of positive samples was 25. Among the 108 positive samples detected by RT‐qPCR, the COVID‐19 antigen (Ag) tests detected 83 cases correctly. All rapid Ag test devices used in this study showed 100% specificity. While tests from six manufacturers had an overall sensitivity range from 75% to 100%, the remaining four tests had a sensitivity of 50%–71.43%. Sensitivity during the first 6 days of symptoms and in samples with high viral loads (C t < 25), was 100% in all but two of the test platforms. False‐negative samples had a median C t of 34 and an average duration of onset of symptoms of 11.3 days (range = 5–20 days). Antigen test diagnosis has high sensitivity and specificity in early disease when patients present less than 7 days of symptom onset. Patients are encouraged to test as soon as they get COVID‐19‐related symptoms within 1 week and to seek medical advice within 24 h if they develop disturbed smell/taste. The use of rapid antigen tests is important for controlling the COVID‐19 pandemic and reducing the burden on molecular diagnostic laboratories.

Diagnostic performance of rapid antigen test for COVID-19 and the effect of viral load, sampling time, subject’s clinical and laboratory parameters on test accuracy

BackgroundEgypt was among the first 10 countries in Africa that experienced COVID-19 cases. The sudden surge in the number of cases is overwhelming the capacity of the national healthcare system, particularly in developing countries. Central to the containment of the ongoing pandemic is the availability of rapid and accurate diagnostic tests that could pinpoint patients at early disease stages. In the current study, we aimed to (1) Evaluate the diagnostic performance of the rapid antigen test (RAT) “Standard™ Q COVID-19 Ag” against reverse transcriptase quantitative real-time PCR (RT-qPCR) in eighty-three swabs collected from COVID-19 suspected individuals showing various demographic features, clinical and radiological findings. (2) Test whether measuring laboratory parameters in participant’s blood would enhance the predictive accuracy of RAT. (3) Identify the most important features that determine the results of both RAT and RT-qPCR. MethodsDiagnostic measurements (e.g. sensitivity, specificity, etc.) and receiver operating characteristic curve were used to assess the clinical performance of “Standard™ Q COVID-19 Ag”. We used the support vector machine (SVM) model to investigate whether measuring laboratory indices would enhance the accuracy of RAT. Moreover, a random forest classification model was used to determine the most important determinants of the results of RAT and RT-qPCR for COVID-19 diagnosis. ResultsThe sensitivity, specificity, and accuracy of RAT were 78.2, 64.2, and 75.9%, respectively. Samples with high viral load and those that were collected within one-week post-symptoms showed the highest sensitivity and accuracy. The SVM modeling showed that measuring laboratory indices did not enhance the predictive accuracy of RAT. Conclusion“Standard™ Q COVID-19 Ag” should not be used alone for COVID-19 diagnosis due to its low diagnostic performance relative to the RT-qPCR. RAT is best used at the early disease stage and in patients with high viral load.

Accuracy of malaria diagnostic tests performed on non-invasively collected samples: a systematic review and meta-analysis

BackgroundDuring the last decade, many studies have assessed the performance of malaria tests on non-invasively collected specimens, but no systematic review has hitherto estimated the overall performance of these tests....

Comparative diagnostic performance of rapid antigen detection tests for COVID-19 in a hospital setting

BackgroundThe availability of accurate and rapid diagnostic tools for COVID-19 is essential for tackling the ongoing pandemic. Our study aimed to quantify the performance of available antigen-detecting rapid diagnostic tests (Ag-RDTs) in a real-world hospital setting. MethodsIn this retrospective analysis, the diagnostic performance of 7 Ag-RDTs was compared with real-time reverse transcription quantitative polymerase chain reaction assay in terms of sensitivity, specificity and expected predictive values. ResultsA total of 321 matched Ag-RDTreal-time reverse transcription quantitative polymerase chain reaction samples were analyzed retrospectively. The overall sensitivity and specificity of the Ag-RDTs was 78.7% and 100%, respectively. However, a wide range of sensitivity estimates by brand (66.0%–93.8%) and cycle threshold (Ct) cut-off values (Ct <25: 96.2%; Ct 30–35: 31.1%) was observed. The optimal Ct cut-off value that maximized sensitivity was 29. ConclusionsThe routine use of Ag-RDTs may be convenient in moderate-to-high intensity settings when high volumes of specimens are tested every day. However, the diagnostic performance of the commercially available tests may differ substantially.

Direct and indirect evidence of efficacy and safety of rapid exercise tests for exertional desaturation in Covid-19: a rapid systematic review

BackgroundEven when resting pulse oximetry is normal in the patient with acute Covid-19, hypoxia can manifest on exertion. We summarise the literature on the performance of different rapid tests for exertional desaturation and draw on this evidence base to provide guidance in the context of acute Covid-19.Main research questionsWhat exercise tests have been used to assess exertional hypoxia at home or in an ambulatory setting in the context of Covid-19 and to what extent have they been validated?What exercise tests have been used to assess exertional hypoxia in other lung conditions, to what extent have they been validated and what is the applicability of these studies to acute Covid-19?MethodAMED, CINAHL, EMBASE MEDLINE, Cochrane and PubMed using LitCovid, Scholar and Google databases were searched to September 2020. Studies where participants had Covid-19 or another lung disease and underwent any form of exercise test which was compared to a reference standard were eligible. Risk of bias was assessed using QUADAS 2. A protocol for the review was published on the Medrxiv database.ResultsOf 47 relevant papers, 15 were empirical studies, of which 11 described an attempt to validate one or more exercise desaturation tests in lung diseases other than Covid-19. In all but one of these, methodological quality was poor or impossible to fully assess. None had been designed as a formal validation study (most used simple tests of correlation). Only one validation study (comparing a 1-min sit-to-stand test [1MSTST] with reference to the 6-min walk test [6MWT] in 107 patients with interstitial lung disease) contained sufficient raw data for us to calculate the sensitivity (88%), specificity (81%) and positive and negative predictive value (79% and 89% respectively) of the 1MSTST. The other 4 empirical studies included two predictive studies on patients with Covid-19, and two on HIV-positive patients with suspected pneumocystis pneumonia. We found no studies on the 40-step walk test (a less demanding test that is widely used in clinical practice to assess Covid-19 patients). Heterogeneity of study design precluded meta-analysis.DiscussionExertional desaturation tests have not yet been validated in patients with (or suspected of having) Covid-19. A stronger evidence base exists for the diagnostic accuracy of the 1MSTST in chronic long-term pulmonary disease; the relative intensity of this test may raise safety concerns in remote consultations or unstable patients. The less strenuous 40-step walk test should be urgently evaluated.

EUCAST rapid antimicrobial susceptibility testing (RAST): analytical performance and impact on patient management.

The emergence of antibiotic-resistant species calls for fast and reliable phenotypic susceptibility testing to adapt clinical management as fast as possible. We assessed the real-life performance of EUCAST rapid antimicrobial susceptibility testing (RAST) and analysed its impact on patient management. RAST was performed on clinical blood cultures containing Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa or Acinetobacter baumannii complex. Categorical agreement with VITEK2 was analysed. A pre-post quasi-experimental observational study was designed to compare antibiotic treatment in sepsis patients in the RAST patient group (n = 51) and a historical control cohort (n = 54). In total, 436 isolates, corresponding to 2314 disc diameters, were measured; 18.4% of these measurements were in the area of technical uncertainty. For the 81.6% categorical results, which could be compared, 94.7% were in agreement, whereas 5.3% of the results were not. In the RAST group, optimal therapy was initiated on the same day as blood culture positivity, while this was the case in the historical group after 24 h. In six cases, RAST allowed for rapid antibiotic escalation. The 30 day mortality rate was lower in the RAST group, although this was not statistically significant. RAST provides a reliable tool to improve clinical management of sepsis patients by providing rapid phenotypic susceptibility data. While not necessarily being an instrument for de-escalation, especially in areas of low prevalence, early detection allows for timely coverage of resistant isolates. Thus, RAST significantly adds to successful antibiotic stewardship programmes.

Evaluation of Analytical Performance of Seven Rapid Antigen Detection Kits for Detection of SARS-CoV-2 Virus.

BackgroundEarly diagnosis of the novel coronavirus disease of 2019 (COVID-19) in asymptomatic and symptomatic patients is crucial to identify infectious individuals and to help prevent the spread of the virus in the community. Several assays have been developed and are in use in today’s clinical practice. These assays vary in their analytical and clinical performance. For an accurate diagnosis, medical professionals must become more familiar with the test’s utility to select the most appropriate test. This study aims to evaluate the analytical performance of rapid antigen tests used for the detection of SARS-CoV-2 viral antigen compared to RT-PCR SARS-CoV-2 molecular assay.MethodsOropharyngeal swab specimens from five COVID-19 patients were tested by seven rapid antigen tests developed by different IVD companies. RT-PCR to detect specific RNA fragments of SARS-CoV-2 was used as a confirmatory test. The cycle threshold (Ct) value, which often reflects viral load, in these specimens ranged from 15 to 35. For the analytical evaluation, extraction fluid of each antigen kit was spiked with attenuated ATCC virus at different concentrations ranging from 4.6x104/mL to 7.5x105/mL and tested with antigen testing kits.ResultsOut of five confirmed positive SARS-CoV-2 specimens by RT-PCR, only one sample showed a positive result by one of the seven evaluated antigen testing kits. The positive result was observed in the specimen with a Ct value of 15. All other evaluated rapid tests were negative for all five positive specimens. This was further confirmed with the spiking study using ATCC attenuated virus, where extraction fluid of each rapid test was spiked with concentrations ranging from 4.6x104/mL to 7.5x105/mL. None of these spiked specimens showed positive results, indicating very low sensitivity of these antigen kits.ConclusionThis comparison study shows that rapid antigen tests are less sensitive than RT-PCR tests and are not reliable tests for testing asymptomatic patients, who often carry low viral load. Analytical performance of rapid antigen tests should be thoroughly evaluated before implementing it at clinical decision level.

Evaluation of binary diagnostic tests accuracy for medical researches

Abstract Objectives The aim of this study is to introduce the features of diagnostic tests. In addition, it will be demonstrated which performance measures can be used for diagnostic tests with binary results, the properties of these measures and how to interpret them. Materials and Methods The evaluation of the diagnostic test performance measures may differ depending on whether the test result is numerical or binary. When the diagnostic test result is continuous numerical data, ROC analysis is often utilized. The performance of a diagnostic test with binary results are usually evaluated using the measures of sensitivity and specificity. However, there are some important measures other than these two measures for binary test results. These measures are predictive values, overall accuracy, diagnostic odds ratio, Youden index, and likelihood ratios. Results A hypothetical data has been produced based on the studies conducted on the performance of rapid tests (Specific IgM/IgG) according to the RT-PCR test for Covid 19 in the literature. An example of a diagnostic test (Specific IgM/IgG) with a binary result is given and all measurements and their confidence interval are obtained for this data. The performance of rapid test was examined and interpreted. Conclusion It is important to design and evaluate the performance of diagnostic/screening tests for health care. In this review, some basic definitions, performance measures that can be used only in evaluating the diagnostic tests with binary results and their confidence intervals are mentioned. Having many different measures provides different interpretations in the evaluation of test performance. Accurately predicting the performance of a diagnostic test depends on many factors. These factors can be study design, criteria of participant selection, sample size calculation, test methods etc. There are guidelines that ensure that all information regarding the conditions under which the study was conducted is in report, in terms of such factors. Therefore, these guidelines are recommended for use of the checklist by many publishers.

Performance of rapid IgM-IgG combined antibody tests in the occupational surveillance of COVID-19 in Colombian enterprises

ResumenIntroducción. Las pruebas combinadas de IgM e IgG rápidas pueden tener un papel importante en la vigilancia de la COVID-19 y en su diagnóstico, así como en la evaluación de la respuesta inmunológica y la verificación de los avances hacia la inmunidad de rebaño. Objetivo. Evaluar el desempeño de las pruebas rápidas de anticuerpos en la vigilancia ocupacional de la COVID-19 en un grupo de empresas colombianas. Materiales y métodos. Se usaron datos de la vigilancia ocupacional de empresas que hicieron pruebas serológicas periódicas a todo el personal desde finales de abril hasta comienzos de julio de 2020. Los trabajadores laboraban en grupos pequeños ("burbujas sociales") para evitar brotes y optimizar la vigilancia. La sensibilidad se estimó como si el muestreo respondiera a un diseño prospectivo. Se describieron, asimismo, los cambios en las pruebas serológicas por medio de rondas periódicas.Resultados. Se obtuvieron datos de 4.740 trabajadores, de los cuales solo 23 eran sintomáticos. En ellos se evidenciaron cambios de IgM(-)/IgG(-) a IgM(+), y luego a IgM(+)/ IgG(+) e IgG(+). La sensibilidad fue de 40,94 % para las IgM(+) y 47,95 % para las IgM(+)/ IgG(+), lo que implica que se pudo detectar un poco menos de la mitad de los casos. Conclusión. Las pruebas rápidas de anticuerpos tienen un papel en el proceso diagnóstico de la infección y deben evaluarse teniendo en cuenta el momento de la epidemia, el tipo de prueba comprada y las poblaciones de riesgo, dado que sus resultados dependen del número de contagios y de casos. En el contexto de la presente crisis sanitaria pueden optimizarse si se organizan los trabajadores en "burbujas sociales".

Evaluation of the performance of rapid tests for screening carriers of acquired ESBL-producing Enterobacterales and their impact on turnaround time

Extended-spectrum β-lactamase (ESBL)-producing Enterobacterales constitute a global burden for hospital infection, and the identification of carriers by screening patients at risk is recommended by several guidelines. To evaluate the impact of rapid ESBL tests on the turnaround time (TAT) of screening. Rectal swabs were analysed by culture and synergism tests for identification of non-Esherichia coli Enterobacterales that produce ESBLs (NEcESBL-producing Enterobacterales). The Rapid ESBL NP and NG CTX-M MULTI tests were performed on colonies grown on chromogenic media. The results of polymerase chain reaction and sequencing of ESBL genes were used as the gold standard. Among 473 analysed swabs, 75 (15.9%) grew NEcESBL-producing Enterobacterales, leading to 89 isolates. Sensitivities of the synergism, Rapid ESBL NP and NG CTX-M MULTI tests were 0.97 [95% confidence interval (CI) 0.88-0.99], 0.81 (95% CI 0.69-0.89) and 0.90 (95% CI 0.80-0.96), respectively. Specificities were 0.92 (95% CI 0.73-0.99), 0.85 (95% CI 0.64-0.95) and 0.96 (95% CI 0.78-1.00), respectively. Considering the 473 rectal swabs, ESBL screening using the synergism, Rapid ESBL NP and NG CTX-M MULTI tests was calculated. Sensitivities were 0.96 (95% CI 0.86-0.99), 0.81 (95% CI 0.68-0.90) and 0.91 (95% CI 0.79-0.97); specificities were 1.00 (95% CI 0.98-1.00), 0.99 (95% CI 0.98-1.00) and 1.00 (95% CI 0.99-1.00); positive predictive values were 0.96 (95% CI 0.86-0.99), 0.94 (95% CI 0.81-0.98) and 1.00 (95% CI 0.91-1.00); and negative predictive values were 1.00 (95% CI 0.98-1.00), 0.98 (95% CI 0.96-0.99) and 0.99 (95% CI 0.97-1.00), respectively. When no NEcESBL-producing Enterobacterales were observed, the mean TAT was 30h. When NEcESBL-producing Enterobacterales were identified, the mean TATs were 74.7, 38.0 and 36.7h for the synergism, Rapid ESBL NP and NG CTX-M MULTI tests, respectively. The two rapid ESBL tests showed good performance and allowed a reduction in TAT for screening protocols to identify patients carrying ESBL-producing Enterobacterales.

Investigation of the rapid immunochromatographic test performance in the diagnosis of syphilis; comparison of four serological methods

AbstractObjectivesTo test the performance of the newly available rapid test for syphilis, we compared it withTreponema pallidumhemagglutination assay (TPHA). Additionally, we investigated the performance of rapid plasma reagin (RPR) and chemiluminescence microparticle immunoassays (CMIA) at our laboratory using TPHA as a gold standard.MethodsThe serum samples of 595 patients with the pre-diagnosis of syphilis were studied by four serological methods. The sensitivity, specificity, and predictive values of RPR, CMIA, and syphilis rapid test were assessed by utilizing TPHA as a gold standard for the diagnosis of syphilis.ResultsOf the patients, 6.2% (37/595) had positive RPR, 5.5% (33/595) had positive CMIA, 5.5% (33/595) had a positive rapid immunochromatographic method and 5% (30/595) had positive TPHA. When TPHA results were taken as the reference, the sensitivity of the rapid test for syphilis was 100%, the specificity was 99.5%, PPV was 90.9%, and NPV was 100.0%.ConclusionsIt was observed that the rapid test for syphilis used in the study was quite successful, its cost was appropriate, and the test was very fast and easy to apply. At the same time, the agreement between syphilis rapid test and TPHA was found to be excellent.

Performance of rapid tests in the management of dengue fever imported cases in Lazio, Italy 2014-2019

BackgroundIn Italy, dengue virus is the most frequent agent of imported viral infections. The use of rapid diagnostic tests (RDTs) may be of help as a preliminary user-friendly quick assay to facilitate dengue diagnosis, as ordinary laboratory diagnosis of dengue fever may require special efforts in terms of tools availability, interpretation of results, and skilled personnel. The performance of RDTs, however, may vary according to different epidemiological and laboratory background. MethodsWe reviewed five years of laboratory records of two dengue RDT results (Colorimetric SD-Bioline Dengue-Duo-RDT and Fluorimetric SD-Biosensor-STANDARD-F-Dengue-RDT), able to detect viral NS1 antigen and specific IgM and IgG. Diagnostic parameters were calculated using as reference the results of molecular (RT-PCR) and serological (immunofluorescence, IFA) tests. Overall performance, calculated considering the final case definition, was included in the accuracy assessment of RDTs. ResultsThe combined use of NS1 and IgM/IgG RDT for the detection of acute dengue cases resulted in an overall sensitivity and specificity of 87.2% and 97.9% for Colorimetric RDT, 96.2% and 96.2% for Fluorimetric RDT. NS1 was the most reliable marker of acute infection, while IgM resulted falsely positive in nine samples, including sera derived from 2 Zika and 4 non-arbovirus infected patients. ConclusionsThe inclusion of RDT in the diagnostic algorithm is of undeniable help in the prompt management and surveillance of dengue infection in non-endemic areas. Confirmatory tests are, however, necessary to rule in or rule out dengue fever diagnosis.

Performance of a novel fluorogenic probe assay for the detection of extended-spectrum-β-lactamase or plasmid AmpC β-lactamase–producing Enterobacterales directly from simulated blood culture bottles

Resistance to third generation cephalosporins is widely disseminated in Enterobacteriaceae mainly because of extended-spectrum-β-lactamases (ESBL), plasmid AmpC β-lactamases (PABL), and hyper-production of chromosomal AmpC β-lactamases. Here, we evaluated the performance of rapid test using novel fluorogenic probe assay in simulated blood cultures and compared the results with the phenol red assay using a total of 172 characterized isolates (39 ESBL producers, 13 PABL producers, and 120 susceptible isolates). We prepared a pellet by centrifugation and washing, which can also be used for identification with MALDI-TOF directly from positive blood cultures. After that, we mixed the pellet with fluorogenic probe and measured the fluorescent signal using fluorometer. The fluorogenic probe assay showed higher sensitivity than the phenol red assay (96.2% vs. 71.2%, p < .0001) in 172 simulated blood culture bottles especially in detecting PABL (84.6% vs. 0%, p = .0026) and the turnaround time was 1.5 h. This fluorogenic probe assay, combined with the direct identification of pathogens, could be very useful for rapid identification of isolates and detecting cephalosporin resistance caused by ESBL and PABL directly from positive blood cultures.

Role of Antifungal Therapy in Complicated Intra-abdominal Infections

In this narrative review, we discuss key questions about the antifungal treatment of complicated intrabdominal infections (cIAI). Although less common than bacteria, Candida spp. are not an infrequent cause of cIAI. Considering that invasive abdominal candidiasis (IAC) may be accompanied by septic shock in up to 40% of cases, empirical antifungal treatment should be considered while waiting for rapid tests and cultures results, and it should be guided by the presence of risk factors for invasive candidiasis in patients with consistent signs and symptoms. Early antifungal therapy before availability of culture results can be partly based on the results of rapid diagnostic tests such as antigen/antibody assays or other rapid methods, although it should be noted that most data pertaining to the use of rapid tests refer to candidemia or invasive candidiasis in general, and not specifically to IAC, thus clinical judgment still remains crucial. Although cultures are hampered by a slow turnaround time, they remain of paramount importance, by allowing identification at species level and antifungal susceptibility testing. Together with source control, adequate antifungal therapy is an essential component of the correct approach to IAC. Future research should focus on enriching our knowledge on the diagnostic performance of rapid tests in cIAI, and on providing a standardized definition for IAC. Advancements in these fields are crucial for improving the correct use of antifungals at the bedside of cIAI patients and also for reducing unnecessary antifungal use in line with antifungal stewardship principles.

Performance of two serodiagnostic tests for loiasis in a Non-Endemic area

Loiasis, caused by the filarial nematode Loa loa, is endemic in Central and West Africa where about 10 million people are infected. There is a scarcity of convenient, commercial diagnostics for L. loa. Microscopy requires trained personnel and has low sensitivity, while the serodiagnosis is currently not standardized. Individual case management is also important in non-endemic countries to treat migrants, expatriates and tourists. We retrospectively compared the performance of a Loa Antibody Rapid Test (RDT) and a commercial ELISA pan-filarial test on 170 patients, 65 with loiasis [8 with eyeworm, 29 with positive microfilaremia, 28 with neither microfilaremia nor history of eyeworm but eosinophilia and history of Calabar swelling (probable loiasis)], 95 with other common parasitic infections and no previous exposure to L. loa (37 with M. perstans, 1 with Brugia sp., 18 with strongyloidiasis, 20 with schistosomiasis, 5 with hookworm, 4 with Ascaris lumbricoides infection, 10 with hyper-reactive malarial splenomegaly), and 10 uninfected controls. The sensitivity of the RDT and of the ELISA were 93.8% (61/65) and 90.8% (59/65), respectively. For the RDT, most of the cross-reactions were observed in patients with M. perstans: 7/37 (18.9%), followed by 1/10 (10%) with hyper-reactive malarial splenomegaly and 1/20 (5%) with schistosomiasis. None of the 27 subjects infected with intestinal nematodes was found positive at this test. The ELISA is meant to be a pan-filarial assay, and reacted extensively with cases of M. perstans (95%), as expected, and also in 11/18 (61.1%) patients with strongyloidiasis and in 3/5 (60%) with hookworm infection. The RDT and the ELISA are both highly sensitive for the diagnosis of loiasis. The main difference lies in the extent of cross-reactivity with other parasites. Considering that the RDT is specifically meant for Loa loa infection, and its high sensitivity, this test could be a useful tool for the diagnosis of occult loiasis.

Low performance of rapid antigen detection test as frontline testing for COVID-19 diagnosis.

Ensuring accurate diagnosis is essential to limit the spread of SARS-CoV-2 and for the clinical management of COVID-19. Although real-time reverse transcription polymerase chain reaction (RT- qPCR) is the current recommended laboratory method to diagnose SARS-CoV-2 acute infection, several factors such as requirement of special equipment and skilled staff limit the use of these time-consuming molecular techniques. Recently, several easy to perform rapid antigen detection tests were developed and recommended in some countries as the first line of diagnostic. The aim of this study was to evaluate the performances of the Coris COVID-19 Ag Respi-Strip test, a rapid immunochromatographic test for the detection of SARS-CoV-2 antigen, in comparison to RT-qPCR. 148 nasopharyngeal swabs were tested. Amongst the 106 positive RT-qPCR samples, 32 were detected by the rapid antigen test, given an overall sensitivity of 30.2%. All the samples detected positive with the antigen rapid test were also positive with RT-qPCR. Higher viral loads are associated with better antigen detection rates. Unfortunately, the overall poor sensitivity of the COVID-19 Ag Respi-Strip does not allow using it alone as the frontline testing for COVID-19 diagnosis.