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Microtiter Plate Antigen-Down Sample Proposals

Antigen-Down Microtiter Plate Immunoassay Sample Quote


In an antigen-down immunoassay, the analyte is coated onto a 96-well microtiter plate (rather than an antibody) and used to bind antibodies found in a sample. When the sample is added (such as human serum), the antigen on the plate is bound by antibodies (human IgE for example) from the sample, which are then retained in the well. A species-specific antibody (such as goat IgG anti-human IgE) labeled with HRP is added next, which binds to the antibody bound to the antigen on the plate. The higher the signal, the more antibodies there are in the sample. Antigen-down assays can be configured as rapid tests and are often used to diagnose allergy conditions - routinely, a patient's blood is tested against different allergens to see if the person has antibodies to that allergen. 

If the target analyte and necessary antibodies are available, assay development generally costs between $30,000 - $100,000 and usually takes 4-8 months. Proposals are often broken down into 4 phases, which detail time and cost estimates. Payments are often structured with a front fee of 30% of the estimated total, and milestone payments disbursed thereafter, which can be paid after each phase or monthly.

When the assay has been developed, we normally supply customers with reagents for 25 immunoassay kits. They can be supplied as individually packaged kits or in bulk packaging (for a detailed description of the reagents in an ELISA kit, see What Are the Typical Components in an ELISA?). When stored at 2o-8o C, each kit may have a shelf life of at least 6 months. If you need more kits, ICT will manufacture the components as you order them (this usually requires a 3-6 week lead-time). Once developed, the cost for additional kits typically ranges from $50 to $300 each (with a minimum manufacturing charge of $2,000). This price will be determined during development and depends on the expense of the kit components, the type of packaging required, and the volume ordered. If you will be testing samples at different locations, we can ship the assay kits directly to the other laboratories (also see Kit Manufacturing).

This sample proposal is meant to answer basic questions, and to act as a project guideline. Depending on your specific project, the amount of antigen required may vary, conjugations may be necessary, the antigen may need to be purified, sample preparation steps may be necessary, and the length of time for the project will vary. In order to answer some of your questions, or to prepare a specific quote for your project, please review the Assay Development Questionnaire, and then contact us. All prices are in US dollars.

Sample Proposal

Antigen-Down Microtiter Plate Assay Development
Required materials and reagents to begin assay development:

  1. Analyte.
  2. Antibodies.
  3. Analyte negative samples.
  4. Analyte positive samples.

Phase I: Reagent Preparation and Initial Assay Titration

Time: 4-8 weeks

  1. Labeling of specific polyclonal antibody (such as goat IgG anti-human IgE) with HRP) for assay signal generation.
  2. Determination of a working titration of capture antigen and detection polyclonal antibody conjugate.
  3. Development and optimization of ELISA plate coating procedures for optimal antibody capture.

Phase II: Assay Optimization

Time: 4-14 weeks

  1. Selection of proper diluents for conjugate signal generation.
  2. Development of special additives to eliminate sample matrix effects such as interference and non-specific binding.
  3. Construction of a standard curve to mimic performance characteristics of the sample matrix.
  4. Development of a functional assay protocol within the target sensitivity range of the target antibody.
  5. Elimination or modification of extraction or sample preparation steps.

Phase III: Assay Validation

Time: 4-5 weeks

  1. Definition and documentation of assay performance characteristics essential for optimal assay utility (such as sensitivity and precision).
  2. Documentation of sample performance parameters such as dilution and linearity and nonspecific background signal generation.
  3. Fine-tuning of specific assay components and incubation protocols to meet final performance requirements.

Phase IV: Production of 25 Finished Kits

Time: 3-4 weeks
1. Quality control assessment of final components.
2. Final assembly, packaging, and delivery of components for 25 ELISA kits.

Total Assay Development Cost: $30,000 - $100,000

Estimated Time: 15-31 weeks

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