Detection Principle

This reagent is manufactured based on the competitive colloidal gold immunochromatographic assay (GICA) principle and exhibits excellent sensitivity toward antibodies against different subtypes of avian influenza virus. After the sample is added to the sample application port, it migrates along the chromatographic membrane together with the AIV antigen and the colloidal gold marker. If the sample contains AIV antibodies, these antibodies will compete with the colloidal gold marker for the AIV antigen, resulting in no purple-red color development on the test line. Conversely, if the sample does not contain AIV antibodies, a color reaction will occur.

Scope of Use

This reagent is used to detect antibodies against avian influenza virus in poultry serum and can be applied to evaluate immune efficacy and assist in diagnosis.

Preservation and Stability

1. The product should be stored in a dry place at a temperature between 2℃ and 30℃ and must not be frozen.

2. Avoid direct sunlight.

3. Valid for 24 months from the date of manufacture.

Sample Requirements

Serum: Collect 2–3 ml of blood using conventional methods and place it into a clean, dry test tube. Allow the blood to clot undisturbed for about 1 hour, then centrifuge at 4,000 r/min for 10 minutes (alternatively, the blood can be left undisturbed for approximately 2 hours until it fully clots and serum naturally separates). Subsequently, carefully separate the serum. The serum must be clear, free from hemolysis and contamination. Short-term storage of serum samples is possible at 2–8℃; for long-term storage, samples should be kept at -20℃.

Whole blood: Whole blood with an anticoagulant added can be used as the test sample (whole blood samples cannot be frozen).

Product Composition

1. Test strips: 1 strip/bag × 40 bags (includes straw)

2. Instruction manual: 1 copy

3. Sample diluent: 40 vials

4. Straws: 40 pieces

Test steps

1. Tear open the aluminum foil packaging of the test card, take out the test card, and place it on a flat, clean work surface.

2. Using the provided straw, draw up the prepared sample and slowly and vertically dispense one drop (approximately 25 μL) into the sample addition port (at this point, observe that no liquid is flowing out of the port).

3. After waiting 10 minutes, use a dropper bottle containing buffer solution to add two drops (approximately 60 μL) of buffer into the sample well.

4. Interpret the results after letting the sample sit at room temperature for 10–15 minutes. Results obtained after more than 30 minutes are invalid.

Note: Adding excessive amounts of sample or buffer may lead to inaccurate results.

Result determination

1. Negative: In the observation window, both the test line region (T) and the control line region (C) show purplish-red lines simultaneously. This indicates that the antibody level is below the HI titer of 1:16.

2. Positive: In the observation window, only the control line region (C) shows a purplish-red line. This indicates that the antibody level is equal to or higher than an HI titer of 1:32.

3. Invalid: No color line appears in the control line region (C) within the observation window.

The detection threshold of this reagent is 1:32 in the hemagglutination inhibition (HI) test. Therefore, by serially diluting the serum to be tested and determining the highest dilution at which the test still yields a positive result, we can calculate the antibody titer. For example, if the serum to be tested is diluted with saline solution at ratios of 1:2 (one part serum plus one part saline), 1:4, and 1:8, and then three different dilution samples are tested—say, both the 1:2 and 1:4 dilutions are positive, while the 1:8 dilution is negative—the highest dilution at which the test remains positive is 1:4. Consequently, the final antibody titer for this sample is calculated as follows: 25 (1:32) multiplied by 2² (1:4), which equals 2⁷ (1:128).