What is the difference between rapid test and swab test？

The new coronavirus is a mutated coronavirus, which can cause pneumonia after human infection. It is an acute respiratory infectious disease. It is very contagious and the population is generally susceptible. It is very easy to replicate in the upper respiratory tract of the human body. Generally, it can be detected in the upper respiratory tract of the human body by means of rapid detection of the new crown nucleic acid within 96 hours of infection with the virus.

The upper respiratory tract of the human body includes the nasal cavity, pharynx, and larynx. That is to say, if a person is infected with the new coronavirus, the nucleic acid of the virus can be extracted from the nasal cavity, pharynx, and larynx within 96 hours. Therefore, we generally sample these locations during the rapid detection of new coronavirus nucleic acid.

We distinguish swabs based on the different sampling locations. For nasal sampling, we become nasopharyngeal swabs; for intraoral sampling, we become oropharyngeal swabs.

In addition to the difference in the sampling site, the nasopharyngeal swab and the oropharyngeal swab also differ in the hardness of the material. Nasopharyngeal swabs are generally slender and soft, and can change shape along the nasal cavity, which is convenient for the sampling personnel to probe into the upper respiratory tract along the nasal cavity. Oropharyngeal swabs are thicker and harder.

There is a big difference between the two in terms of comfort. Due to the frequent exchange of gas in the nasal cavity, when sampling, the swab should be completely inserted into the end of the nasal cavity to ensure that a sufficient concentration of samples is collected, which often causes great discomfort to the person being collected, and sometimes even Causes nasal bleeding. The oropharyngeal swab only needs to collect a sample of the pharynx, and only needs to open the mouth of the person to be collected. Although it occasionally causes a short-term nausea, the discomfort will not last for too long.

There is also a significant difference between the two in terms of toxicity. Studies have shown that in patients infected with the new coronavirus, the viral load on nasopharyngeal swabs is significantly higher than that on oropharyngeal swabs. That is to say, in terms of detection amount, nasopharyngeal swabs are generally higher than oropharyngeal swabs.

In addition to nasopharyngeal and oropharyngeal swabs, there are also anal swabs. As the name suggests, anal swab is to collect samples from the anus of the subject. It is a test for patients with gastrointestinal symptoms, which can effectively improve the detection rate. However, due to the inconvenience of sampling, it is not widely used.

Immediately after the swab sampling is completed, the swab will be placed in a storage tube to avoid contamination of the sample. After the sampling is completed, the subsequent rapid detection process of new crown nucleic acid can be carried out. No matter what kind of swab it is, the process for the rapid detection of new crown nucleic acid is the same. The rapid detection of new crown nucleic acid is completed in the laboratory reagent preparation area, sample preparation area, amplification area, and product analysis area, which are independently separated from each other. The results of the rapid nucleic acid test for the new coronavirus.

The rapid test is divided into antigen test and antibody test. Antigen test diagnoses active infection through saliva sampling, and antibody test shows whether you have been infected with coronavirus in the past through blood sampling . Antigen test needs to be equipped with an analyzer, which is not suitable for household use. Currently, the household quick kits on the market are serum antibody tests, which are easy to operate. There are four main steps:

1. Wipe your fingers with an alcohol tablet

2. Open the one-time convenience needle and press on the belly of the finger

3. Use a pipette to suck blood droplets to the detection plate

Fourth, drop two drops of diluent, let stand for fifteen minutes and wait for the result

After the quick test is completed, the results are analyzed. IgG positive means that antibodies have been produced in the body for a period of time and have been infected with coronavirus, which does not indicate the current virus replication situation.

       IgM positive means that antibodies have just been produced in the body, and the virus is still actively replicating in the early stage of coronavirus infection.