Detection of SARS-CoV-2 by antigen ELISA test is highly swayed by viral load and sample storage condition

Abstract Background Hepatitis B virus (HBV) infection is a major concern for blood safety in high-prevalence HBV countries such as China. In Shenzhen, dual hepatitis B surface antigen (HBsAg) enzyme-linked immunosorbent assays (ELISAs) have been adopted in parallel with nucleic acid testing (NAT) for donors for over a decade. A small proportion of blood donors test reactive (R) for HBsAg but negative through routine NAT, which can lead to HBV infection with an extremely low viral load. Objectives We aimed to investigate and analyze the molecular characteristics of HBV among blood donors that tested HBsAg R in a single ELISA test. Methods Blood donations were evaluated in this study if confirmed HBsAg R through one of two ELISA kits. Samples with non-reactive (NR) results by NAT were collected and tested for HBsAg by chemiluminescent microparticle immunoassay (CLIA) with a neutralization test. The level of HBsAg was further assessed by electrochemiluminescence immunoassay (ECLIA). The viral basic core promoter (BCP) and pre-core (PC) and S regions were amplified by nested PCR. Quantitative real-time PCR (qPCR) for viral load determination and individual donation (ID)-NAT were adopted simultaneously. HBsAg was confirmed with CLIA, ECLIA, nested PCR, qPCR, and ID-NAT. Results Of the 100,252 donations, 38 and 41 were identified as HBsAg R with Wantai and DiaSorin ELISA kits, respectively. Seventy-nine (0.077%, 79/100,252) blood samples with ELISA R-NR and NAT NR results were enrolled in the study. Of these, 17 (21.5%,17/79) were confirmed as HBsAg-positive. Of the 14 genotyped cases, 78.6% (11/14) were genotype B, and C and D were observed in two and one sample, respectively. Mutations were found in the S gene, including Y100C, Y103I, G145R, and L175S, which can affect the detection of HBsAg. A high-frequency mutation, T1719G (93.3%), was detected in the BCP/PC region, which reduced the viral replication. Conclusion A small number of blood samples with HBsAg ELISA R-NR and NAT NR results were confirmed as HBV infection, viral nucleic acids were found in most of the samples through routine NAT methods. It is necessary to employ more sensitive and specific assays for the detection of HBV infection among blood donors.

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Comparative Diagnosis of Serum IgG1 and Coproantigen ELISA for Fasciolosis Detection of Goats in Mexico

BioMed Research International ◽

10.1155/2016/3860928 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Abel Villa-Mancera ◽

Pedro Molina-Mendoza ◽

Karina Hernández-Guzmán ◽

Jaime Olivares-Pérez ◽

Jorge Sarracent-Pérez ◽

...

Keyword(s):

Serological Test ◽

Sandwich Elisa ◽

Correlation Coefficients ◽

Economic Loss ◽

Elisa Test ◽

Current Status ◽

Antigen Elisa ◽

Faecal Samples ◽

Diagnostic Sensitivity And Specificity ◽

Serum Elisa

The objective of present study was to determine the prevalence of natural caprine fasciolosis in the Mixteca region of Mexico using coproantigen and serum IgG1 ELISA tests for comparative purposes. A total of 1070 serum and faecal samples were analyzed for IgG1 antibodies and coproantigens, using ELISA with E/S products as antigen and a monoclonal antibody-based sandwich ELISA. Prevalence of 73.46% was found using the serological ELISA and a percentage of 77.20 was found for coproantigen ELISA. The diagnostic sensitivity and specificity for serum ELISA were 86.7% and 96.4%, and for the coproantigen ELISA they were 93.1% and 97.8%, respectively. The seropositive samples were further categorized as low, medium, or high positivity. Results show a great proportion of low and medium positive goats when the serum ELISA test was used. Correlation coefficients between coproantigens and seropositivity were statistically significant (P<0.01) for low seropositivity (r=0.93) and medium seropositivity (r=0.84). The accuracy of faecal antigen ELISA was higher compared to indirect ELISA serological test. Two ELISAs were shown to be useful for demonstrating the current status ofF. hepaticainfection in the endemic areas and can be employed in studies on epidemiology as well as anthelmintics treatment for preventing economic loss and the risk of transmission to humans.

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PO 8425 THE DIAGNOSTIC AND PROGNOSTIC VALUE OF NEW URINE-BASED LEISHMANIA ANTIGEN DETECTION TESTS

BMJ Global Health ◽

10.1136/bmjgh-2019-edc.93 ◽

2019 ◽

Vol 4 (Suppl 3) ◽

pp. A36.1-A36

Author(s):

Salah Boshara

Keyword(s):

Visceral Leishmaniasis ◽

Rapid Test ◽

Elisa Test ◽

Lateral Flow ◽

Lateral Flow Assay ◽

Serological Tests ◽

Kala Azar ◽

Antigen Elisa ◽

Protozoan Infection ◽

Monitoring Treatment

BackgroundVisceral leishmaniasis (VL) also known as kala-azar, is a protozoan infection caused by the L. donovani complex and transmitted by sandflies. Early detection of leishmaniasis is critical in management of patients and for successful control and elimination of the disease. Definitive diagnosis of visceral leishmaniasis is by parasitological demonstration of parasites in splenic, lymph node or bone marrow aspirates, which are collected using invasive methods that are unsuitable in the field. This study aimed to evaluate new less invasive urine-based ELISA and rapid diagnostic test (RDT) assays for diagnosis of VL.MethodsThe newly developed urine ELISA test was evaluated using archived and fresh urine samples collected from parasitologically confirmed VL patients and non-VL cases. Lateral flow assay (LFA) using the ELISA reagents were conducted for day0 samples. Serological tests (DAT, rk28 ICT) were conducted for every patient in the study.ResultsIn 198 patients with suspected VL, urine rapid test had a sensitivity of 72.2% and exhibited a specificity of 93.42%. Leishmania antigen ELISA had a sensitivity of 83.33% and a specificity of 95.05%. All VL-confirmed cases were followed up during the treatment period, the Leishmania antigen ELISA became negative 2 months after completion of treatment in most patients.ConclusionUrine lateral flow assay is a simple addition to the diagnostics of VL particularly at field level and as a complementary test for the diagnosis of VL in smear-negative cases. Further enhancement of the test will define its performance in monitoring treatment. Further studies are recommended to evaluate the performance of both tests in the diagnosis of HIV-co-infected cases.

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Measurement of steroid hormones in saliva: Effects of sample storage condition

Scandinavian Journal of Clinical and Laboratory Investigation ◽

10.3109/00365513.2013.835862 ◽

2013 ◽

Vol 73 (8) ◽

pp. 615-621 ◽

Cited By ~ 37

Author(s):

Rebecca J. Toone ◽

Oliver J. Peacock ◽

Alan A. Smith ◽

Dylan Thompson ◽

Scott Drawer ◽

...

Keyword(s):

Steroid Hormones ◽

Storage Condition ◽

Sample Storage

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Variations of gut microbiome profile under different storage conditions and preservation periods: A multi-dimensional evaluation

10.1101/752584 ◽

2019 ◽

Cited By ~ 1

Author(s):

Junli Ma ◽

Lili Sheng ◽

Chuchu Xi ◽

Yu Gu ◽

Ying Hong ◽

...

Keyword(s):

16S Rrna ◽

Gene Sequencing ◽

16S Rrna Gene Sequencing ◽

Storage Condition ◽

Storage Conditions ◽

Rrna Gene ◽

Sample Storage ◽

Sequencing Platform ◽

Microbiome Profile ◽

Rrna Gene Sequencing

ABSTRACTGut dysbiosis contributes to the development of various human diseases. There are thousands of publications per year for investigating the role of gut microbiota in development of various diseases. However, emerging evidence has indicated data inconsistency between different studies frequently, but gained very little attention by scientists. There are many factors that can cause data variation and inconsistency during the process of microbiota study, in particular, sample storage conditions and subsequent sequencing process. Here, we systemically evaluated the impacts of six fecal sample storage conditions (including −80 °C, −80 °C with 70% ethanol (ET_-80 °C), 4°C with 70% ethanol (ET_4°C), and three commercial storage reagents including OMNIgene•GUT OMR-200 (GT), MGIEasy (MGIE), and Longsee (LS)), storage periods (1, 2 weeks or 6 months), and sequencing platform on gut microbiome profile using 16S rRNA gene sequencing. Our results suggested that −80°C is acceptable for fecal sample storage, and the addition of 70% ethanol offers some benefits. Meanwhile, we found that samples in ET_4 °Cand GT reagents are comparable, both introduced multi-dimensional variations. The use of MGIE resulted in the least alteration, while the greatest changes were observed in samples stored in LS reagents during the whole experiment. Finally, we also confirmed that variations caused by storage condition were larger than that of storage time and sequencing platform.IMPORTANCEIn the current study, we performed a multi-dimensional evaluation on the variations introduced by types of storage conditions, preservation period and sequencing platform on the basis of data acquired from 16S rRNA gene sequencing. The efficacy of preservation methods was comprehensively evaluated by DNA yield and quality, α and β diversity, relative abundance of the dominant bacteria and functional bacteria associated with SCFAs producing and BAs metabolism. Our results confirmed that variations introduced by storage condition were larger than that of storage periods and sequencing platform. Collectively, our study provided a comprehensive view to the impacts of storage conditions, storage times, and sequencing platform on gut microbial profile.

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Intact parasite-antigen ELISA test: a new dimension for serodiagnosis of Amoebiasis

Journal of Applied and Natural Science ◽

10.31018/jans.v10i3.1835 ◽

2018 ◽

Vol 10 (3) ◽

pp. 976-980

Author(s):

Archana Mishra ◽

Ajay Kumar Sharma ◽

Vandana Tewari

Keyword(s):

Clinical Trials ◽

Entamoeba Histolytica ◽

Epidemiological Survey ◽

Elisa Test ◽

Parasite Antigen ◽

Antigen Elisa ◽

Circulating Antibodies

An Intact Parasite Antigen ELISA (IPA-ELISA) has been developed for detection of circulating antibodies against Entamoeba. histolytica. Axenically grown trophozoites of E.histolytica (NIH-200) after glutaraldehyde treatment, are used as Intact Parasite Antigen (IPA) as well biological active and imperishable base. Antigen over the surface of treated cells were allowed to interact with the antibody molecules of the test sera. The techniques of Plate, Dot-and IPA-ELISA are compared of their merits for clinical and epidemiological survey of amoebiasis. IPA-ELISA was found to be more sensitive (96.8%) and specific (92.3%) in detecting circulating antibodies compared to Plate-ELISA (sensitivity 90.5%, specificity 84.6%) and Do-ELISA (sensitivity 92.1%, specificity 86.1%). The entire IPA-ELISA test could be completed within 3 hours. Costwise IPA-ELISA is several times lesser than Dot-and Plate-ELISA. This test is most suitable for field and clinical trials for suspected cases of amoebiasis with no skilled hand required for diagnosis.

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