There are many factors in the "single positive" situation that need to be retested to improve the accuracy of nucleic acid testing

According to reports, at 17:00 on November 1, the Department of Disease Control and Prevention of Changping, Chaoyang District, Beijing, notified that the nucleic acid test results of two people were positive and single-gene positive

The nucleic acid test result is positive for a single gene? As soon as this term came out, it became the "mysterious single yang" of the entire network

How does nucleic acid testing work?

"Single positive results are generally less likely

In the "New Coronavirus Pneumonia Prevention and Control Plan (Eighth Edition)", the technical guidelines for the collection and detection of new coronavirus samples (hereinafter referred to as the guidelines) are clearly stipulated: The method of nucleic acid detection in the laboratory adopts "real-time fluorescent RT-PCR "Methods to detect the nucleic acid of the new coronavirus

So, why does the nucleic acid of the new coronavirus fluoresce when it comes?

The guide specifies special matching "primers", which are designed for the unique genes in the new coronavirus genome (two new coronavirus reporter genes are selected: open reading frame 1ab and nucleocapsid protein)

The fluorescence is weak.

Two targets mean that two "undercovers" were sent in this investigation system

Did "Shan Yang" report wrong?

But from the results, "Single Yang" means that two "undercovers" gave completely different answers, one positive and one negative

Is this "split" answer due to a problem with the detection system?

Pang Nian thought it was unlikely

Regarding the quality control of nucleic acid testing, the guidelines stipulate that the China Centers for Disease Control and Prevention shall carry out quality control assessments for laboratories of provincial-level disease control institutions at least once a year, and at the same time provide a national new coronavirus laboratory testing quality control program

When it comes to large-scale population screening, the guidelines clearly stipulate that once a positive result appears, another 1-2 more sensitive nucleic acid detection reagents should be used to recheck the original sample for the positive sample, and the positive result can be reported

It can be seen that the results of nucleic acid testing have "three insurances" in terms of technology and equipment, laboratory assessment, and review

Is "Single Yang" positive?

So, how to interpret "Single Yang"?

"The emergence of'single yang' is related to many factors, including the infection status of the virus, the type of test samples, and the standardization of sample sampling operations

The guidelines also provide for "case confirmation": if a single target is positive, re-sampling and re-testing are required

In addition, fluorescent nucleic acid detection can be qualitative or quantitative.