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Hemagglutination Inhibition Assay (HAI)

Hemagglutination inhibition (HI or HAI) is used to determine relative concentrations of viruses, bacteria, or antibodies invented by American virologist George Hearst in 1941. This experimental method utilizes surface proteins of various viruses (such as hemagglutinin (HA) of influenza virus) to agglutinate multiple types of red blood cells (RBC). The reaction of viral hemagglutinin with red blood cells produces a lattice of aggregated cells. However, if the serum of a person infected with the virus is mixed with RBC and the virus, RBC will not agglutinate. This phenomenon is called hemagglutination inhibition. Antibodies present in the infected person's serum neutralize the virus, which leads to a positive result. If the patient's serum does not contain antibodies against the surface protein of the test virus, there will be a hemagglutination reaction because the surface molecule is free for the hemagglutinin RBC (negative result).

Our Procedures

  • Obtain a preparation of virus (e.g., influenza viruses) with a known HA titer or determine its HA titer.
  • Prepare two-fold dilutions of patient/test serum to be tested, e.g., from 1:4 to 1:1024.
  • Add a fixed amount of virus to every well of a 96-well plate, equivalent to 4 HA units (varies according to the virus), except for the serum control wells.
  • Allow the plate to stand at room temperature for 60 minutes (time varies according to specific requirements).
  • Add RBCs and incubate at four °C for 30 minutes.
  • Read the wells.

HAI is closely related to HA analysis, mainly through antiviral antibodies as "inhibitors" that interfere with the interaction of viruses and RBCs. The purpose is to characterize the concentration of antibodies in antiserum or other samples containing antibodies. HAI assay is usually performed by creating antiserum dilutions serially in each well of a 96-well microtiter plate. A standard amount of virus or bacteria will be added to each well, and the mixture will be incubated at room temperature. It is necessary to set up a negative control without adding virus for each sample. During the incubation, the antibody will bind to the virus particles. If the antibody concentration and its binding affinity are sufficiently high, the blood coagulation reaction can be effectively blocked.

Our Capabilities

  • Abroviruses-togaviruses (rubella)
  • Flavivirus
  • Mononucleosis
  • Orthomyxovirus (influenza)
  • Paramyxovirus (measles, mumps)
  • Bunyaviruses

Our Virus HAI Services

  • BSL-2 live virus,inactived virus, antigens
  • The one-week fresh red blood cells from SPF turkey, chicken, guinea pig, and/or swine
  • Select and optimize the most suitable antiviral antibody
  • Hemagglutination inhibition assay

Our Advantages

  • Ensure high efficiency and quality for HAI services
  • Competitive price in the market of HAI services
  • Ensure 24/7 online service
  • Timely result feedback

We combine infection and analytical expertise to provide our clients with the most powerful portfolio of antiviral and antimicrobial in vitro testing services. Facing an increasing demand for new antiviral and antimicrobial compounds for the treatment of infectious diseases, Creative Diagnostics can test these compounds in vitro to determine their potential efficacy in vivo models.


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We Are Providing Our Clients Antiviral & Antibacterial Services

Having extensive knowledge in cell biology and the application of cell-based assays to benefit clients in the drug and vaccine development industry

Offering comprehensive solutions to drive your projects to completion

Delivering prompt quotations and competitive prices

Providing quality science and personalized customer service

Antiviral Services - Creative Diagnostics

Creative Diagnostics provides expertise in antiviral (or antibacterial) assays and cell-based antiviral (or antibacterial) compound screening to other biotechnology and pharmaceutical companies.

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