The principles of pet rapid detection mainly include immunoassay technology, molecular biology technology, biochemical analysis technology and microscopy technology. The specific introduction is as follows:

Immunoassay Technology

• Colloidal Gold Immunochromatography: This is one of the most commonly used techniques in pet rapid detection. It utilizes the specific binding between antigens and antibodies. Colloidal gold particles are conjugated with specific antibodies. When a sample containing the target antigen (such as the antigen of canine distemper virus) is added to the test strip, the antigen will bind to the antibody-conjugated colloidal gold particles. Then, they migrate along the strip and react with the immobilized antibodies on the test line, forming a colored band. The intensity of the color can roughly indicate the amount of antigen in the sample. This method is simple, rapid, and can provide results within 10 – 15 minutes, which is suitable for on-site and rapid screening of pet diseases.
• Enzyme-Linked Immunosorbent Assay (ELISA): ELISA is also widely used in pet rapid detection. It is based on the specific binding of antigens and antibodies and the catalytic function of enzymes. The antigen or antibody is first immobilized on the surface of a microplate. Then, the sample and the enzyme-labeled antibody or antigen are added and allowed to react. After washing away the unbound substances, a substrate is added. The enzyme-labeled antibody or antigen catalyzes the substrate to produce a color reaction. The intensity of the color is measured by a spectrophotometer, which is proportional to the amount of the target substance in the sample. ELISA has high sensitivity and specificity and can quantitatively detect various substances in pet samples, such as hormones, cytokines and pathogen antigens.

Molecular Biology Technology

• Polymerase Chain Reaction (PCR): PCR is a key technology for detecting pet pathogens and genetic diseases. It can amplify specific DNA sequences in a pet’s sample exponentially. Firstly, the DNA in the sample is extracted. Then, specific primers that are complementary to the target DNA sequence are designed. In the PCR reaction system, under the action of DNA polymerase, the primers bind to the target DNA and initiate DNA replication. After multiple cycles of denaturation, annealing and extension, a large number of copies of the target DNA are obtained. The amplified DNA products can be detected by gel electrophoresis or other methods. PCR is highly sensitive and specific and can detect very low levels of pathogen DNA or genetic mutations in pets.
• Loop-Mediated Isothermal Amplification (LAMP): LAMP is a new type of nucleic acid amplification technology. It uses multiple specific primers to recognize six different regions on the target DNA sequence and can complete nucleic acid amplification under isothermal conditions, usually at 60 – 65°C. The reaction does not require complex temperature control equipment and can be completed in a relatively short time, usually within 30 – 60 minutes. The amplified products can be judged by visual inspection of turbidity or color change, or by electrophoresis. LAMP has advantages such as high efficiency, simplicity and rapidity in the detection of pet infectious diseases and is suitable for use in grass-roots unit laboratories and field detection.

Biochemical Analysis Technology

• Photometry: In pet rapid detection, photometry is often used to measure the concentration of various biochemical substances in the blood or other body fluids of pets. For example, the concentration of glucose, creatinine and other substances can be determined by measuring the light absorption of the sample at a specific wavelength. The sample is mixed with a specific reagent to produce a color reaction, and the degree of color change is proportional to the concentration of the substance to be measured. The concentration of the substance in the sample can be calculated by comparing with the standard curve.
• Electrochemical Analysis: Electrochemical analysis technology detects the electrochemical properties of substances in pet samples, such as potential, current and conductivity. For example, in the detection of blood potassium and blood sodium ions in pets, ion-selective electrodes are used. These electrodes have a selective response to specific ions. When in contact with the sample, an electrochemical potential difference is generated, which is related to the concentration of the ions in the sample. By measuring this potential difference, the concentration of ions in the sample can be determined.

Microscopy Technology

• Optical Microscopy: Optical microscopy is a basic detection method in pet medicine. It can be used to observe the morphology and structure of cells, microorganisms and parasites in pet samples. For example, by observing the smear of pet feces under an optical microscope, the eggs and trophozoites of parasites such as roundworms and coccidia can be directly observed. In the examination of blood smears, the morphology and number of red blood cells, white blood cells and platelets can be observed to judge whether there are blood system diseases.
• Fluorescence Microscopy: Fluorescence microscopy uses fluorescent substances to label specific targets in pet samples. The labeled targets emit fluorescence under the excitation of specific light, which can be observed and analyzed under a fluorescence microscope. For example, fluorescent antibodies can be used to label pathogen antigens in pet tissues or cells. By observing the fluorescence distribution and intensity, the presence and location of pathogens can be determined. This method has high sensitivity and specificity and is helpful for the accurate diagnosis of pet diseases.