Wide Variability in the Sensitivity and Specificity of Rotavirus Immunoassay Diagnostic Kits in Practice

Introduction: Most hospitals rely on rapid antigen-detection kits for the diagnosis of rotavirus infection. Several small studies reviewed the sensitivity and specificity of some of these kits. These studies showed discrepancy in results obtained for sensitivity and specificity that varied according to the type of kit used, area of study, and type of test used as standard for diagnosis of rotavirus infection. The objective of the study is to determine the sensitivity and specificity of five commonly used rotavirus immunoassay kits in comparison to RT-PCR as standard. Methodology: Stool samples (N = 1,414) collected from children under 5 years of age hospitalized with gastroenteritis were tested for rotavirus by immunoassay kits and RT-PCR in a prospective hospital-based surveillance study conducted at 7 centers in Lebanon. Concordance and discrepancy between the two methods was used to calculate sensitivity and specificity, using RT-PCR as the “gold standard”. Results: The sensitivity and specificity were respectively 95.08% and 86.62% for the SD Bioline® (Standard Diagnostics, Inc, South Korea) kit calculated on 645 samples, 65.86% and 45.90% for the VIROTECT® (Trinity Biotech, Ireland) kit calculated on 327 samples, 83.9% and 64.2% for the Rota-Strip (C-1001) (Coris Bioconcept, Belgium) calculated on 95 samples, 52.3% and 10.9% for the Acon® (Acon Laboratories, Inc, California, USA) kit calculated on 122 samples, 68.1% and 20% for the VIKIA® Rota-Adéno (Biomerieux, France) kit calculated on 32 samples. Conclusion: A wide discrepancy was detected between the calculated and advertised sensitivity and specificity for most of the kits.

Study of Various Diagnostic Tests for COVID-19: A Review

The coronavirus disease of 2019 (COVID-19), a nightmare of this century, has become an ongoing global health emergency for the entire world. This dreadful disease is believed to have originated from China and has now spread worldwide. To date, more than 170 million people have been found affected by this virus, namely “severe acute respiratory syndrome coronavirus-2” (SARS-CoV-2). With the exponential increase in the patients affected by the SARS-CoV-2, the need for testing has also increased tremendously. Early diagnosis is essential to prevent the extensive spread of the disease because of the faster rate of infection. In this regard, various diagnostic techniques are employed for the detection of the infection in symptomatic and asymptomatic COVID-19 individuals. To provide diagnostic care for the control of the disease, various tests like serological testing, nucleic acid amplification test (NAAT), rapid antigen-based testing, and paper-based testing have been developed and are presently in good use. The present mini-review is an attempt to outline the currently available diagnostic kits for the detection of the SARS-CoV-2 causing COVID-19.

Diagnostic Accuracy of Rapid Diagnostic Kits Test for Diagnosis of Malaria

Objective: To assess the diagnostic accuracy of rapid diagnostic kits test for diagnosis of malaria taking microscopy as gold standard Methodology: A total of 375 cases with age range 18-65 years of either gender as suspected for malaria were included in the study. We excluded all those cases already taking anti-malarial drugs. The study was conducted at Chughtais Lahore Lab, Lahore. Required blood sample were obtained following aseptic measures. Malaria RDT SD Bioline Malaria Antigen Pf/Pan (Catalogue No. 05FK60, Standard Diagnostics Inc, Hagal-Dong, Korea, from now on referred as “SD RDT”) was used. Patients were labeled as positive or negative on the basis of reports from hematology department assessed by microscopy and patients were labeled as positive or negative Results: The mean age of the patients was 41.84±13.44 years, male to female ratio of the patients was 1.01:1. The sensitivity, specificity, and diagnostic accuracy of the RDT for diagnosing malaria was 96.79%, 96.28% and 96.53% respectively taking microscopy as gold standard Conclusion: Rapid diagnostic kits is very useful reliable test with high diagnostic accuracy for diagnosis of malaria taking microscopy as gold standard Keywords: Microscopy, Rapid Diagnostic kits, Malaria,

Development of an Enzyme-Linked Immunosorbent Assay (ELISA) for Accurate and Prompt Coronavirus Disease 2019 (COVID-19) Diagnosis Using the Rational Selection of Serological Biomarkers

Prompt COVID-19 diagnosis is urgently required to support infection control measures. Currently available serological tests for measuring SARS-CoV-2 antibodies use different target antigens, although their sensitivity and specificity presents a challenge. We aimed to develop an “in-house” serological ELISA to measure antibodies against SARS-CoV-2 by combining different protein antigens. Sera (n = 44) from COVID-19-confirmed patients were evaluated against different SARS-CoV-2 protein antigens and all potential combinations using ELISA. Patients’ sera were also evaluated against commercially available ELISA diagnostic kits. The mixture containing RBD 2.5 μg/mL, S2 1 μg/mL and N 1.5 μg/mL was found to be the most potent. Plates were incubated with patients’ sera (1:100), and goat anti-human alkaline phosphatase-conjugated IgG, ΙgM and IgA antibody was added. The cut-off value for each assay was determined using the mean optical density plus two standard deviations of pre-pandemic controls. The “in-house” ELISA displayed 91% sensitivity and 97% specificity for IgG antibodies, whereas its sensitivity and specificity for IgM and IgA were 75% and 95% and 73% and 91%, respectively. The “in-house” ELISA developed here combined three SARS-CoV-2 antigens (RBD, S2 and N) as capture antigens and displayed comparable and even higher sensitivity and specificity than otherwise quite reliable commercially available ELISA diagnostic kits.

An inventory of diagnostic tools for detection of COVID-19

: The ongoing pandemic of coronavirus disease 2019 (COVID-19) caused by SARS-COV-2 has afflicted millions of lives globally and disrupted almost all the activities of mankind. Under such pressing circumstances when there are no effective therapeutics available, fast and accurate diagnosis of the corona virus is the only way out to limit the transmission. Since the inception of COVID-19, the demand of diagnostic tests has increased day by day and RT-PCR is the commonly used screening test which is not only time consuming but requires sophisticated resources. To address the increasing rate of spread of COVID-19, there is an urgent need of more diagnostic tools as the researches on vaccines is still at rudimentary level. This review summarizes an inventory on the diverse and currently available diagnostic methods based on nucleic acid and serology along with some of those working on novel principles viz. CRISPR, biosensors and NGS. Additionally, a gist of accessible diagnostic kits that are already approved by US & European authorities for the diagnosis of COVID-19 are also suggested that will help in selecting most effective tests under the given scenario. Taken together, this review will pave way for further strengthening the researches in the rapid and safer diagnostics of SARS-COV-2.

A Simple and Fast Method to Sequence the Full-Length Spike Gene for SARS-CoV-2 Variant Identification from Patient Samples

Since the beginning of the pandemic, a race has been underway to detect SARS-CoV-2 virus infection (PCR screening, serological diagnostic kits), treat patients (drug repurposing, standard care) and develop a vaccine. After almost a year of active circulation worldwide, SARS-CoV-2 variants have appeared in different countries. Those variants include mutations in multiple regions of the genome, particularly in the spike gene. Because this surface protein is a key player in both the spread of the virus and the efficacy of vaccine strategies, the challenge is to efficiently monitor the appearance of spike mutations in the population. The present work describes a procedure based on the widely available Sanger technology to produce a full-length sequence of the spike gene from patient-derived samples.

PERSISTENCE OF MALARIALANTIGEN FOLLOWING ANTIMALARIAL CHEMOTHERAPY IN KOLKATA, WEST BENGAL

Early diagnosis and complete treatment is one of the important aspects of malaria elimination programme worldwide. In many areas the diagnosis is based on detection of malarial antigen using commercially available rapid diagnostic kits. The problem remains with persistence of antigen following parasite clearance by proper treatment. The present work was undertaken to study the pattern of persistent antigen of P. vivax and P. falciparum following antimalarial treatment. Atotal of 300 microscopically positive mono-infected with P. vivax (160) and P. vivax (140) patients were recruited, treated with antimalarial drugs and followed up on day 3, 7, 14, 21 and 28 for persistent parasites and antigen. P. vivax specic pLDH antigen was disappeared from peripheral blood within 14 days post treatment period. P. falciparum specic HRP-2 antigen was persisted even after 28 days of treatment. Depending only on antigen based diagnosis, attention should be paid before treatment, particularly in areas with high malaria transmission