Evaluation of a rapid antigen test (Panbio™ COVID-19 Ag rapid test device) for SARS-CoV-2 detection in asymptomatic close contacts of COVID-19 patients

ObjectivesThere is limited information on the performance of rapid antigen detection (RAD) tests to identify SARS-CoV-2-infected asymptomatic individuals. In this field study, we evaluated the Panbio? COVID-19 Ag Rapid Test Device (Abbott Diagnostics, Jena, Germany) for this purpose.MethodsA total of 634 individuals (355 female; median age, 37 years; range, 9–87) were enrolled. Two nasopharyngeal swabs were collected from household (n = 338) and non-household contacts (n = 296) of COVID-19 cases. RAD testing was carried out at the point of care. The RT-PCR test used was the TaqPath COVID-19 Combo Kit (Thermo Fisher Scientific, MA, USA).ResultsHousehold contacts were tested at a median of 2 days (range, 1–7) after diagnosis of the index case, whereas non-household contacts (n = 296) were tested at a median of 6 days (range, 1–7) after exposure. In total, 79 individuals (12.4%) tested positive by RT-PCR, of whom 38 (48.1%) yielded positive RAD results. The overall sensitivity and specificity of the RAD test was 48.1% (95% CI 37.4–58.9) and 100% (95% CI 99.3–100), respectively. Sensitivity was higher in household (50.8%; 95% CI 38.9–62.5) than in non-household (35.7%; 95% CI 16.3–61.2%) contacts. Individuals testing positive by RAD test were more likely (p < 0.001) to become symptomatic than their negative counterparts.DiscussionThe Panbio test displays low sensitivity in asymptomatic close contacts of COVID-19 patients, particularly in non-household contacts. Nonetheless, establishing the optimal timing for upper respiratory tract collection in this group seems imperative to pinpoint test sensitivity.     

Proteinuria is common among HIV patients: what are we missing?

OBJECTIVES:HIV-related renal diseases are the leading causes of chronic kidney diseases worldwide. The present study aimed to investigate the prevalence of pathological proteinuria and its risk factors among HIV patients.METHODS:A review of the medical records of 666 HIV-infected individuals aged 18 years or older in an urban HIV/AIDS clinic based in Porto Alegre in southern Brazil. Overt proteinuria was defined as a protein-to-creatinine ratio greater than 150 mg/g according to Kidney Disease: Improving Global Outcomes.RESULTS:The prevalence of pathological proteinuria in the present study cohort was 20%. Characteristics associated with pathological proteinuria after univariate analysis included alcohol abuse, hepatitis C virus coinfection, the occurrence of diabetes and therapy including tenofovir. Adjusted residuals analysis indicated an association between pathological proteinuria and both a CD4 lymphocyte count below 200 cells/mm³ and a viral load higher than 1000 copies/mL. Additionally, an absence of pathological proteinuria was associated with a CD4 lymphocyte count higher than 500 cells/mm³. After adjustment for variables with p<0.2 in the univariate analysis using a Poisson regression model, tenofovir-containing regimens and a CD4 lymphocyte count below 200 cells/mm³ were significantly associated with pathological proteinuria.CONCLUSION:The risk of chronic kidney diseases in this large contemporary cohort of HIV-infected individuals appeared to be attributable to a combination of HIV-related risk factors. In addition to the traditional risk factors cited in the literature, both regimens containing tenofovir and HIV disease severity seem to be associated with chronic kidney diseases in patients with HIV. Assessment of proteinuria constitutes a novel method for chronic kidney disease staging in HIV-infected individuals and may be effectively used to stratify the risk of progression to end-stage renal disease.     

Comparison of serologic tests with urinary antigen detection for diagnosis of legionnaires’ disease in patients with community-acquired pneumonia

ObjectiveTo compare serologic methods and detection of urinary antigen in the diagnosis of community-acquired pneumonia.MethodsPaired sera from 84 patients with community-acquired pneumonia were tested for Legionella pneumophila serogroup (LP SG) 1–7 and Legionella micdadei by use of the indirect immunofluorescence antibody test (IIF), enzyme-linked immunosorbent assay (ELISA) for LP SG 1–7 and complement-fixation (CF) test for LP SG 1. All patients were evaluated by ELISA urinary antigen detection for LP SG 1.ResultsSeven patients met the CDC criteria for acute Legionella infection, while in the rest of them we failed to detect urinary Legionella antigen. Thirty-three patients had non-diagnostic IIF antibody titers. Serum ELISA (IgG and/or IgM) was positive in 40 patients. Nine patients showed at least one CF titer of ≤1:32. The sensitivities of ELISA IgM for the first and the second serum samples compared with IIF were 42.8% and 46.6%, respectively, while the specificities were higher, i.e. 87% and 88.4%, respectively. The sensitivities of ELISA IgG for the first and the second samples were 42.8% and 53.3%, and the specificities were 77.9% and 76.8%, respectively.ConclusionsAlthough ELISA is simple to perform and easy to automate, we think that its advantages over indirect immunofluorescence and urinary antigen detection remain questionable.     

Multicenter evaluation of the Panbio™ COVID-19 rapid antigen-detection test for the diagnosis of SARS-CoV-2 infection

ObjectivesThe standard RT-PCR assay for coronavirus disease 2019 (COVID-19) is laborious and time-consuming, limiting testing availability. Rapid antigen-detection tests are faster and less expensive; however, the reliability of these tests must be validated before they can be used widely. The objective of this study was to determine the performance of the Panbio? COVID-19 Ag Rapid Test Device (PanbioRT) (Abbott) in detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in nasopharyngeal swab specimens.MethodsThis prospective multicentre study was carried out in ten Spanish university hospitals and included individuals with clinical symptoms or epidemiological criteria of COVID-19. Only individuals with ≤7 days from the onset of symptoms or from exposure to a confirmed case of COVID-19 were included. Two nasopharyngeal samples were taken to perform the PanbioRT as a point-of-care test and a diagnostic RT-PCR test.ResultsAmong the 958 patients studied, 325 (90.5%) had true-positive results. The overall sensitivity and specificity for the PanbioRT were 90.5% (95%CI 87.5–93.6) and 98.8% (95%CI 98–99.7), respectively. Sensitivity in participants who had a threshold cycle (C_T) < 25 for the RT-PCR test was 99.5% (95%CI 98.4–100), and in participants with ≤5 days of the clinical course it was 91.8% (95%CI 88.8–94.8). Agreement between techniques was 95.7% (κ score 0.90; 95%CI 0.88–0.93).ConclusionsThe PanbioRT performs well clinically, with even more reliable results for patients with a shorter clinical course of the disease or a higher viral load. The results must be interpreted based on the local epidemiological context.     

Are we missing a simple treatment for most adult sleep apnea patients? The avoidance of the supine sleep position

Obstructive sleep apnea (OSA) is a sleep disorder which has been gradually accepted as an important cause of increased morbidity and mortality. The treatment of moderate–severe OSA has improved dramatically since the introduction of continuous positive airway pressure (CPAP) devices; however, the adherence of patients to CPAP treatment is relatively low. Adherence appears to be even worse in patients with mild or asymptomatic OSA. The failure to identify and treat mildly symptomatic or asymptomatic OSA patients may be costly, as such patients comprise about 20% of the general adult population. OSA patients could be divided into positional and non‐positional patients. Positional patients show most of their breathing abnormalities while sleeping in the supine position. Simply, by sleeping in the lateral postures, they eliminate or reduce significantly the number of apneas and hypopneas. On the contrary, non‐positional patients suffer from breathing abnormalities in the supine and lateral postures, and as a consequence those are the most severe OSA patients for whom CPAP is the treatment of choice. In this paper we intend to argue that positional therapy, i.e. avoidance of the supine posture during sleep, could represent a valuable therapy mainly for mild–moderate OSA. Considering the fact that the vast majority of mild–moderate OSA patients are positional patients (between 65 and 87%), positional therapy may be a simple, cheap and effective solution for them. High‐quality research regarding this issue is needed to evaluate the real effectiveness of this mode of therapy.     

Which complement assays and typings are necessary for the diagnosis of complement deficiency in patients with lupus erythematosus? A study of 25 patients

INTRODUCTION: Deficiencies in components of the classical pathway of complement activation are strong risk factors for lupus erythematosus (LE).Yet, it has not been addressed whether the conventional measurements of the serum hemolytic CH50 activity and antigenic concentrations of C3 and C4 are sufficient to asses a deficiency in C4A, C4B or C2 components, the most common deficiencies associated with LE. PATIENTS AND METHODS: In a retrospective series, we performed complement analyses in 35 patients with LE who were systematically screened for a complement deficiency. The majority of patients had cutaneous LE with mild systemic involvement and no complement consumption. Of 25 patients (72%) with complement deficiency we found 13 with a partial C4A deficiency, 2 with a complete C4A deficiency, 6 with a partial C4B deficiency, 2 with a complete C4B deficiency and 2 with a combined partial C2 and C4A deficiency. RESULTS: The total complement activity (CH50) was decreased in only one out of two patients with complete C4B deficiency. CH50 level was found to be low-normal (35-38 U/ml(-1)) in one patient with partial C4B deficiency, one patient with complete C4B deficiency and both patients with combined partial C4A and C2 deficiency. Total C4 levels were normal in 9 out of 13 the patients with a partial C4A deficiency and in 2 out of 6 patients with a complete C4B deficiency. The antigenic concentration of C3 was low in only 1 patients with a complete C4B deficiency and within the normal range in all the others patients. Overall, 50% of the patients had normal or elevated C3, C4, and CH50 levels. DISCUSSION: This study emphasizes that the usual measurements of CH50, C3 and C4 levels are not adequate to detect a C4 and/or C2 deficiency in patients with LE. In epidemiologic or investigative studies addressing the prevalence of complement deficiency, more elaborated diagnostic tests, such as C4 protein allotyping, C2 level measurement and genetic screening for type I C2 deficiency should also be performed.     

Do we have suitable in-vitro diagnostic tests for the diagnosis of food allergy?

PURPOSE OF REVIEW: Positive standardized food challenges represent the gold standard of diagnostic procedures in food-related reactions suspected to be of allergic nature. Skin prick testing and in-vitro diagnosis is helpful in most cases and can help to avoid cumbersome food challenges. This review considers recent progress in the use of in-vitro tests in the diagnosis of food allergy. RECENT FINDINGS: Recent studies have addressed the characterization of 'new' food allergens which might now be used more accurately in the in-vitro diagnosis of food allergy. Additionally, while in-vitro tests must always be interpreted in line with the allergen tested and the clinical history, levels of food-specific immunoglobulin E can be correlated with the outcome of challenges to foods such as tree nuts as well as egg, according to two recent studies. Finally, epitope binding patterns of specific food allergens might help to predict which patients will most likely outgrow their food allergy, or which patients are clinically tolerant. This might help to avoid food challenges, which carry a risk for a potentially severe outcome. SUMMARY: Recent studies of in-vitro diagnosis of food allergy have helped to provide safer and more accurate tests in the diagnosis and prognosis of food allergy.     

Evaluation of the SD BIOLINE TB Ag MPT64 Rapid® for the diagnosis of tuberculosis

The purpose of this study was to evaluate the SD Bioline Ag MPT64 Rapid^® for identification of the Mycobacterium tuberculosis complex. The method uses an immunochromatographic assay and needs 100 μl of sample taken from liquid culture or colonies suspended. The sensitivity was determined using 99 strains of M. tuberculosis complex and the specificity using 10 nontuberculous mycobacteria and 85 strains other than mycobacteria genus. The test showed excellent sensitivity (99%) and specificity (100%). This technique displays several advantages and is destined to spread in all laboratories and particularly in endemic areas.     

PTEN immunohistochemistry in endometrial hyperplasia: which are the optimal criteria for the diagnosis of precancer?

Guidelines recommend protein phosphatase and tensin homolog (PTEN) immunohistochemistry for differentiating between benign endometrial hyperplasia (BEH) and atypical endometrial hyperplasia/endometrioid intraepithelial neoplasia (AEH/EIN). However, it is unclear when PTEN expression should be defined as ‘lost’ and thus suggestive of AEH/EIN. We aimed to determine the optimal immunohistochemical criteria to define PTEN loss in endometrial hyperplasia, through a systematic review and meta‐analysis of diagnostic accuracy. Electronic databases were searched for studies assessing immunohistochemical expression of PTEN in both BEH and AEH/EIN specimens. PTEN status (‘loss’ or ‘presence’) was the index test; histological diagnosis (‘AEH/EIN’ or ‘BEH’) was the reference standard. Accuracy was quantified based on the area under the curve (AUC) on summary receiver operating characteristic (SROC) curves, for several different thresholds of PTEN expression. Eighteen studies with 1362 hyperplasias were included. Six different criteria to define PTEN loss were assessed. Low diagnostic accuracy was found for complete loss of expression (AUC = 0.71), presence of any null gland (AUC = 0.63), positive cells <10% (AUC = 0.64), positive cells <50% (AUC = 0.71) and moderate‐to‐null intensity (AUC = 0.64). Barely moderate diagnostic accuracy was only found for the subjective criterion ‘weak‐to‐null intensity’ (AUC = 0.78). Therefore, the clinical usefulness of PTEN immunohistochemistry in this field should be further investigated.     

What do we know about the antibody responses to SARS-CoV-2?

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread worldwide causing a pandemic with millions of infected people and deaths. Currently, the scientific community is working hard to develop a specific vaccine or treatment. However, since antibody production is an important part of the adaptive immune response, to develop vaccines and therapies, we must understand the antibody response to SARS-CoV-2 infection. In this work, we summarize the most important findings of antibody-mediated immunity against SARS-CoV-2 and highlight its role in the efficient use of plasma from convalescent patients and the direct application of antibodies as treatment.     

What are the current best immunohistochemical markers for the diagnosis of epithelioid mesothelioma? A review and update

Numerous immunohistochemical markers that can assist in the diagnosis of epithelioid mesotheliomas, some of which have only recently been recognized, are currently available. Because the various types of carcinomas express these markers differently, their selection for inclusion in a diagnostic panel can vary according to the differential diagnosis. This article provides a critical review of all of the information that is presently available on those markers that are believed to have the greatest potential for assisting in distinguishing between epithelioid mesotheliomas and those carcinomas with which they are most likely to be confused. Information is also provided regarding the panels of immunohistochemical markers that are, at present, recommended in these differential diagnoses.