Will antigen testing replace rapid nucleic acid testing for new crowns as anti-immune guidelines are updated?

In order to do a good job of prevention and control of the New Coronavirus epidemic scientifically, and to adapt to the characteristics of the current epidemic, which is "multi-point, extensive and frequent", the "Guidelines for the Organization and Implementation of Regional Novel Coronavirus Nucleic Acid Testing (New Coronavirus Rapid Nucleic Acid Testing) (Third Edition)" clearly introduced the "antigen screening, nucleic acid diagnosis The surveillance model of "antigen screening, nucleic acid diagnosis" was introduced.

The Guide proposes that "localities can combine the requirements of the new coronavirus antigen detection, promote the monitoring model of "antigen screening, nucleic acid diagnosis", increase antigen testing as a complementary means of regional new coronavirus nucleic acid rapid test, study and refine the implementation plan and then organize and implement. " .

The adjustment of the "Guidelines" brings more scientific and precise prevention and control requirements for the prevention and treatment of neocrown pneumonia.

Therefore, antigen testing has attracted widespread attention in recent times, and what kind of method is this? Will it be able to replace the traditional rapid nucleic acid test for new coronary pneumonia in future rapid tests? Let's talk about it today.

The general method used for antigen screening is the colloidal gold method, which is performed by colloidal gold test paper. This is what we currently call the colloidal gold method. The most common type of colloidal gold is the "early pregnancy" and other pregnancy tests.

This test paper is specially marked with holes for dropping the sample into the test subject. There are two lines on the colloidal gold test paper, one is called the test line and the other is called the quality control line. If both lines are colored, it means positive; if only the quality control line is colored, it means negative; other than these two cases, it is an invalid result. That is, we often say "a bar", "two bars".

This test method is convenient and very fast, generally in about 10-15 minutes, you can get the test results.

Although its detection speed is advantageous, but its sensitivity and specificity is far from enough, that is, the accuracy is not enough. In addition, its detection throughput is low, and there is a certain rate of misclassification (mainly affected by the perceived operation and the quality of the antigen); moreover, the antibody to the new coronavirus detected by the colloidal gold method is an IgM antibody, and IgM is produced later than the time of virus replication, so the time window of detection is narrower than that of nucleic acid detection, which means that it is generally difficult to detect at the early stage of infection, and needs to go through the patient's body immune system to produce the corresponding This means that it is generally difficult to detect the infection at the initial stage, and it is necessary for the patient's immune system to produce the appropriate antibodies before it can be reported.

Therefore, the antigenic method is still not an alternative to the NICR for epidemic prevention and control. Likewise, it is not suitable for use in areas with low infection rates and cannot be used in large numbers at important junctures in epidemic prevention and control because of its low accuracy, which can cause misclassification in the early stages of infection, healed individuals, etc.

Compared to most of the current rapid testing methods, the Nucleic Acid Rapid Test is still the "gold standard" for patient diagnosis.

Although the Nucleic Acid Rapid Test is not yet able to report results within minutes like other methods, through the improvement of technology and the automation of the entire process of the Nucleic Acid Rapid Test, and the continuous iteration of testing reagents, the Nucleic Acid Rapid Test is now able to complete the purification and amplification of nucleic acid within a few hours, contributing to the accurate prevention and control of the epidemic.

The current other rapid detection methods can be used as a potential risk screening means in large-scale screening, as a complementary means of the new crown nucleic acid rapid test.