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Official Description

Hemagglutination inhibition test (HAI)

© Copyright 2026 American Medical Association. All rights reserved.

Common Language Description

The Hemagglutination Inhibition (HAI) test, designated by CPT® Code 86280, is a laboratory procedure utilized for the identification of specific viruses or bacteria. This test is characterized by its simplicity, rapid execution, and high accuracy in detecting the presence of antigens or quantifying antibodies. The underlying principle of the HAI test involves the interaction between surface proteins of certain viruses and bacteria with red blood cells, leading to a phenomenon known as agglutination, where these pathogens clump together with the red blood cells to form a lattice-like structure. In the HAI test, a known quantity of antibodies is mixed with the antigen of interest and a fixed amount of red blood cells that are coated with the corresponding antigen. If the sample being tested contains the specific antigen, it will compete with the antigen coated on the red blood cells for binding to the introduced antibodies. This competition inhibits the agglutination process, allowing for the identification or quantification of the antigen or antibody present in the sample. The HAI test is a valuable tool in clinical diagnostics, providing essential information for the detection of infectious agents.

© Copyright 2026 Coding Ahead. All rights reserved.

1. Indications

The Hemagglutination Inhibition (HAI) test is performed for various clinical indications, particularly in the context of infectious diseases. The following conditions may warrant the use of this test:

  • Identification of Viral Infections The HAI test is commonly used to identify specific viral infections, particularly those caused by viruses that exhibit hemagglutination properties.
  • Detection of Bacterial Infections This test can also be utilized to detect certain bacterial infections that involve antigens capable of agglutinating red blood cells.
  • Quantification of Antibodies The HAI test is effective in quantifying antibodies in a patient's serum, which can be crucial for diagnosing immune responses to infections.

2. Procedure

The Hemagglutination Inhibition (HAI) test involves several key procedural steps that ensure accurate results. The following outlines the procedure:

  • Step 1: Sample Preparation A sample of the patient's serum is collected and prepared for testing. This may involve centrifugation to separate the serum from blood cells, ensuring that only the liquid portion containing antibodies is used in the test.
  • Step 2: Antigen Coating Red blood cells are coated with a specific antigen that corresponds to the virus or bacteria being tested. This coating is essential for the agglutination process, as it allows the red blood cells to interact with the antibodies in the patient's serum.
  • Step 3: Mixing A fixed amount of the prepared serum is mixed with the antigen-coated red blood cells in a controlled environment. This mixture is incubated to allow for any potential reactions between the antibodies and the antigens.
  • Step 4: Observation After incubation, the mixture is observed for agglutination. If agglutination occurs, it indicates that the antibodies in the serum have bound to the antigens on the red blood cells, suggesting the absence of the specific antigen in the sample. Conversely, if agglutination is inhibited, it indicates the presence of the antigen in the sample.

3. Post-Procedure

Following the Hemagglutination Inhibition (HAI) test, the results are analyzed to determine the presence or absence of the specific antigen or to quantify the antibodies. Depending on the findings, further clinical evaluation may be necessary. If the test indicates a positive result for a viral or bacterial infection, appropriate treatment options can be discussed with the patient. Additionally, it is important to document the results accurately for future reference and to inform any necessary follow-up testing or interventions. The patient may be advised on any further steps based on the test outcomes, including potential treatments or additional diagnostic procedures.

Short Descr HEMAGGLUTINATION INHIBITION
Medium Descr HEMAGGLUTINATION INHIBITION TEST HAI
Long Descr Hemagglutination inhibition test (HAI)
Status Code Statutory Exclusion (from MPFS, may be paid under other methodologies)
Global Days XXX - Global Concept Does Not Apply
PC/TC Indicator (26, TC) 9 - Not Applicable
Multiple Procedures (51) 9 - Concept does not apply.
Bilateral Surgery (50) 9 - Concept does not apply.
Physician Supervisions 09 - Concept does not apply.
Assistant Surgeon (80, 82) 9 - Concept does not apply.
Co-Surgeons (62) 9 - Concept does not apply.
Team Surgery (66) 9 - Concept does not apply.
Diagnostic Imaging Family 99 - Concept Does Not Apply
CLIA Waived (QW) No
APC Status Indicator Conditionally packaged laboratory tests
Type of Service (TOS) 5 - Diagnostic Laboratory
Berenson-Eggers TOS (BETOS) T1H - Lab tests - other (non-Medicare fee schedule)
MUE 1
CCS Clinical Classification 235 - Other Laboratory
Date
Action
Notes
Pre-1990 Added Code added.
Code
Description
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