In the evening of February 22, 2020, the State Drug Administration issued an announcement, following the Spring Festival nucleic acid test reagents for the new coronavirus received state approval for registration, the new emergency approval of three new coronavirus detection products submitted by three companies, including two colloidal gold antibody test reagents, a thermostatic amplification chip method nucleic acid test reagents.
Nucleic acid detection method and antigen antibody detection method are two types of detection methods on the new coronavirus
Nucleic acid assays
Nucleic acid (DNA or RNA) is the genetic material of the virus.
The results can be determined by extracting "special" gene sequence fragments, "amplifying" them, and "replicating" them in large quantities.
Antigen-antibody assay
A specific binding reaction between an antigen and an antibody is used.
Nucleic acid testing can be classified as
Gene sequencing
Interpretation and analysis of new and unknown viral nucleic acids
Time required: 5 days for sequencing of new coronavirus genes
Disadvantages: The full sequence of the virus is more expensive, the results need to be analyzed and
interpreted by professionals, and it takes longer.
Polymerase chain reaction (PCR)
This technique is widely used in molecular biology experiments.
Disadvantages: the operation is more tedious and prone to aerosol infection of laboratory operators.
Fluorescence quantitative PCR assay (second generation PCR technique)
The current official recommended technical method for detecting novel coronaviruses.
Improved sensitivity and specificity compared to other PCR techniques.
Constant temperature amplification technique
Compared to the precise temperature control required for PCR technology, thermostatic amplification technology requires less instrument temperature.
Disadvantage: professionals are required to perform the specific steps and the results are prone to false positives.
"Rapid detection": antigen-antibody detection
Direct method / indirect method
Using the principle of specific binding of antigen and antibody, colloidal gold detection is used to determine the presence of infection by detecting an unknown antigen with a known antibody or an unknown antibody with a known antigen.
The antibodies are mainly classified as immunoglobulin M (IgM) and immunoglobulin G (IgG), and a positive test can be used as an indicator of presenting infection and previous infection, respectively.
This method is less time consuming and does not require special instruments.
Disadvantages: The antibody test has a window period and cannot detect early infections, and there are certain false negatives and false positives.
At present, the kits for the "rapid test" are subject to review and confirmation by the pharmacovigilance department.
