Recently, the amount of nucleic acid testing and antibody testing in our country has increased. More and more people have done the three tests for new coronary pneumonia screening: nucleic acid, IgM and IgG. You may have heard of it. So what is the significance of the testing indicators?
What's wrong with the nucleic acid test, mainly false negatives, that is, take a throat swab and poke it into the nose and turn it around to bring out the virus inside.
However, if the sampled virus is small and the storage time is long, the virus will die before the inspection, and it will not be detected. Such a result is called a false negative, and the patient is detected to be okay, and he is allowed to run around, resulting in a cluster of infections.
Therefore, most hospitals require patients to be tested for antibodies, that is, immunoglobulin, which is called IG (immune globulin) in English, and blood is drawn.
Compared with throat swabs, this operation is simpler. Almost all hospitals can take blood. But before the new coronary pneumonia, throat swabs were done in few places, and the staff who did throat swabs faced the patient’s nose. The pharynx, as recently as the virus, is actually very dangerous.
There are 5 kinds of human immunoglobulins. Two of the most important are IgM and IgG.
IGM is the first to appear after infection and can be understood as an anti-virus commando. According to the seventh edition of the guidelines, the new coronavirus commando starts to appear 3-5 days after the onset of illness, so IgM can also screen some patients. A positive IGM indicates an early infection.
However, this commando has a small number of people, with only less than 10% of immunoglobulins. It can only play a role in probing and harassment, and has very limited ability to fight the virus. And it lasts for a short time, not in a few weeks
After that, a large force came, that is, IgG, the main immune globulin of the human body, accounting for about 70 to 75% of the total amount of Ig in the blood, and it mainly depends on him to fight the virus.
After winning, IgG will also exist in the body for a long time, and some can last for decades. Basically, IgG positive means that you have immunity to this virus and it is difficult to infect again.
Based on this knowledge point, you can interpret the situation of new coronary pneumonia.
To give a few examples:
1. Test within 3-5 days of infection. Generally, the nucleic acid is positive, and both IGG and IGM are negative, because the immunoglobulin has not been formed yet.
2. After 5 days, both nucleic acid and IGM are positive. At this time, the body begins to have an early immune response.
3. In a few days, all three indicators may be positive. This is the time when the infection is most active, but the body already has a certain degree of immunity.
4. In a few days, the nucleic acid will turn negative, indicating that the virus has been eliminated, but the body's IGM and IGG are still positive, and the patient can be discharged from the hospital at this time.
5. In a few days, both the nucleic acid and IGM will turn negative and enter the recovery period. At this time, the IGG test is positive, which means that I have been infected with new coronary pneumonia before, but I am healed now.
6. After a few years, all 3 of them may be negative. If a normal person has never been in contact, all 3 of them are negative. ·
