Immunoassay Testing Services

Immunoassay testing is a highly selective bioanalytical method that measures the presence or concentration of analytes ranging from small molecules to macromolecules in a solution. Understanding when and how to use immunoassays can be critical throughout the development lifetime of CGT products.

Immunoassays have a variety of applications in CGT development

Immunoassays are based on the principle of using an antibody or an antigen as a biorecognition agent. Harnassing the unqiue binding properties of these antibodies enables accurate quantification of specific biological molecules and cells.

However, immunoassays require rigorous optimisation and validation to ensure accuracy. Having multiple methods to measure your target gives you robust, reliable results.


In the context of biologics, immunoassay testing is routinely used to:

  • quantify different immune cell populations in blood and sera as part of immunological response characterisation
  • quality control cell lines donors (as per USFDA guidance)
  • detect presence of protein(s) or cell(s) of interest
  • detect of neutralising antibodies that can effect potency of viral biologics

Immunoassays also have a range of applications outside of CGT products. To find out more about this, visit our pages on multiplexed assays and immunoassay validation.


The Absorption Systems Difference

Absorption Systems is a GLP/GMP facility offering support from early drug discovery through Phase IV clinical trials. Our team has many years of experience in the development and validation of immunoassays for compound screening, ADA, Nab, PK, biomarkers testing using a variety of methodologies. We provide a white-glove service covering all aspects of your immunoassay needs from preparing sample collection kits and training clinical sites for proper specimen management to creating FDA-ready validation and/or sample analysis reports. You are kept up to date on all aspects of your projects through weekly progress reports and/or teleconferences. 



What do your immunoassay formats include?

  • Bridging
  • Competitive technique
  • Direct binding study
  • HACA
  • HAMA
  • Immunogenicity 
  • Immunoglobulin Screening
  • Isotyping
  • Client Specific Assay Formats


How are immunoassays validated?

  • Performance Characteristics – Parameters such as reproducibility, operator-to-operator variation, sample parallelism, sensitivity, specificity, beginning to end variation, assay ruggedness, spike and recovery, freeze-thaw effects and cutoff analysis can be performed to evaluate the performance of the particular assay.
  • Assay Acceptability Criteria – Acceptability parameters are established from the validation, which then are used for the determination of assay acceptability. Control charts are utilized to track assay performance and trends that may occur over time. By using this method, overall performance can be monitored assay-to-assay, operator-to-operator, and day-to-day.
  • Supporting Documentation – Depending upon the client’s requirements, Standard Operating Procedures (SOP’s), worksheets, and reagent logs are generated and incorporated into the TGA BioServices QA documentation system, resulting in full traceability of all analysis.
  • Database Formation and Handling – Specific macros are tailored to each project to ensure that all raw data is electronically transferred during database generation and statistical analysis, thereby eliminating manual input errors.


What is Quantitative Western Blot analysis?

Western blot analysis is an immunological testing method that can detect a protein of interest from a mixture of a great number of proteins. Western blotting generates information about the size of a protein and how that protein is expressed when compared directly to a control sample. Samples for analysis can include cells, tissues, and synthesized recombinant proteins. The success of the western blot method depends upon the quality and specificity of the antibodies used to detect a response against a specific protein of interest.


Does Absorption Systems offer GLP and cGMP methods of Western Blot testing?

Absorption Systems can generate a method for a western blot utilized in either R&D applications or in a GLP/cGMP study. There is an additional charge for GLP and cGMP methods as compared to R&D projects. Using the Syngene System, western blots can be quantitated through the GeneSnap Software and particular methods can be validated for use in clinical trials.


Our capabilities include:

  • Measurement of small molecules, peptides, and large proteins for R&D or product release (cGMP)
  • Immunoassays for the monitoring of antibody or protein levels throughout a clinical study in complete compliance with GLP guidelines
  • Development of an immunoassay-based screening protocol against your lead compound
  • Assay design and detection systems for antibodies with unique specifications; quantitative detection systems for antibodies with unique specifications
  • Quantitative detection systems for the determination of contaminants in highly purified products
  • Immunoassays utilized for the detection of cytokines or cell surface markers
  • Use of commercial kits in compliance with cGMP or GLP guidelines
  • Monoclonal antibody screening (Western blot or ELISA)


Our most common immunoassay methodologies include:

    • Validate the commercial kits, assay transfer or develop the test from the scratch (LDT)
    • Can perform Assay Qualification, RUO Validation, and GxP Validation
    • Any applications related to antigen-antibodies interaction
    • Large molecules and protein PK studies
    • ADA, TAb, NAb detection
  • Quantitative Western Blot
  • Enzyme Activity Assays


ELISpot and FluoroSpot

  • assays in 96-well plates allow rapid analysis of large numbers of samples
  • quantification of the number of cytokine (for example IFN-γ or TNF-α) secreting cells.
  • The ELISPOT assay can be used to determine effects of drugs or other compounds on cytokine secretion in vitro.
  • Monocytes/macrophages/dendritic cells characterization
  • Apolipoproteins analysis
  • The ELISPOT assay can be used to determine the frequency of antigen-specific cytotoxic T cells (CTL) in fresh unstimulated peripheral blood.

Luminex technology is based on the principles of Flow Cytometry. It uses a single 5.6 micron size microspehere that are dyed with red and infrared dyes in different combinations to create 500 uniquely colored microspheres. Luminex bead array assays are widely used for:

  • rapid biomarker quantification.
  • asessment of serological immunity after successful vaccination
  • assessment of immunogenicity
  • cytokines, chemokines and growth factors
  • cell signaling pathways
  • adverse effect diagnosis, for example, cytokine storm, by comparing a baseline samples to various time points after administration of vaccines