Author: bioaxxess

False-positives in Covid-19 testing?

False-positives in Covid-19 testing?

The Covid-19 antibody test challenge

Dr. Tobias Polifke & Dr. Peter Rauch, CANDOR Bioscience GmbH, Wangen, Germany

In the current situation of the Covid-19 pandemic, reliable IgG antibody tests are urgently needed all around the world. Virologists caution against cross-reactivities that could potentially lead to false positives.

Using ELISAs as an example, we discuss the technical requirements for the development of truly dependable immunological testing methods, since the cross-reactivities debated by many virologists constitute only a small fraction of the actual challenges.


Discover Peviva Products

Discover Peviva Products

Since 2011 BIOAXXESS acts as the distributor of VLVbio (formerly PEVIVA AB) for customers in the UK and the Republic of Ireland (ROI).

Our scientific and technical expertise with PEVIVA’s M30 and M65 ELISA and Cytokeratin-18 antibodies stems back to 2003. This is when BIOAXXESS started trading as a business and technology development agency for PEVIVA (now VLVbio) in Europe.

The list of Cytokeratin-18 projects initiated and coached to successful conclusion, includes efficacy and safety testing for drug development in oncology, but also diagnostic applications in hepatology (NASH, NAFLD and AoCLD), sepsis and Graft-versus-Host Disease (GvHD).

Through our long-standing and broad experience of our in-house PhD-level expertise, we are able to support your project, whether you are based at a university, hospital, CRO, clinical research centre or working on R&D within pharma and biotech.

At BIOAXXESS we focus on customers’ needs and offering unrivalled support from pilot project to large clinical studies.

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Product Release to aid the development and manufacturing of better Covid-19 Antibody Tests (05/2020)

Product Release to aid the development and manufacturing of better Covid-19 Antibody Tests (05/2020)

As part of BIOAXXESS UK’s continued efforts to support the challenge to develop reliable SARS-CoV-2 (Covid-19) antibody tests, we are pleased to announce CANDOR Bioscience’s new PlateBlockTM blocking reagent that has shown superior surface blocking results for ELISA-based immunoassays for Covid-19 and other types of infectious disease diagnostics. 

PlateBlockTM efficiently blocks unspecific binding of IgG antibodies in human serum samples to the ELISA plate.

How CANDOR Bioscience products can help the development of better Covid-19 antibody tests:

Use PlateBlockTM  to minimise the number of false positive results for antigen-down ELISAs detecting high-affinity anti-SARS-CoV-2 IgG antibodies in patient blood samples diluted as low as 1:10 to allow for excellent sensitivity in serological tests.

Combine low background with superior specificity for SARS-CoV-2 by using CANDOR’s LowCross-Buffer® as anti-interference sample dilution buffer.

LowCross-Buffer® acts as an “affinity filter” that excludes assay signals due to low to medium affinity antibodies that may be already present against other related corona viruses from previous infections.

Instead, zoom in on human antibodies with high affinity to SARS-CoV-2 that are expected to confer Covid-19 immunity in asymptomatic individuals or those who experienced only mild Covid-19 symptoms.

The same approach is crucial for the assessment of immunity in healthy individuals currently taking part in clinical studies of experimental vaccine projects against SARS-CoV-2.

BIOAXXESS are pleased to offer CANDOR’s ELISA Sampler Package CoViD-19 as a tool box, which contains the novel PlateBlockTM together with the key CANDOR reagents required for professional ELISA development and manufacturing.

CANDOR Bioscience just published two White Papers on how their products, including the new PlateBlockTM can help to design, develop and manufacturer high quality Covid-19 antibody tests for routine laboratory use (in vitro diagnostic assays, ELISA):

 Specificity, positive predictive value and validation statistics in the context of CoViD-19  NEW

See Fig. 4 on PlateBlockTMcompared to other ELISA plate blockers as taken from CANDOR’s White Paper  ‘Covid-19 Antibody Test Challenge’.

 CoViD-19-antibody-test-challenge  NEW