I. Enzyme-linked immunosorbent assay

At present, there are 8 kinds of ELISA methods used. Their specificity and sensitivity are above 99%.

Second, the particle agglutination method (PA)

PA is a quick and simple screening method. If it is positive, it should be confirmed by WB. PA does not need any special instruments, and the naked eye can distinguish the results. The whole process only takes 5 minutes. Disadvantages are false positives and expensive.

Third, rapid reagents.

(1) Diagnostic reagent for human immunodeficiency virus 1+2 antibody (colloidal selenium method)

Abbott's human immunodeficiency virus antibody diagnostic reagent (colloidal selenium method) is used for in vitro, naked eye observation, qualitative immunoassay, detection of HIV- 1 and HIV-2 antibodies in serum or plasma, and helps individuals infected with HIV- 1 and HIV-2 antibodies. This product is only used for on-site screening of unpaid blood donors and clinical emergencies. People who test positive for this product need further screening and confirmation.

(II) InstantCHEKTM-HIVl+2 gold-labeled rapid diagnostic reagent

InstantCHEKTM-HIV 1+2 is a rapid, simple and sensitive method to detect HIV- 1 and HIV-2 antibodies. This method is suitable for the primary screening test, and those who are positive by this reagent need to be detected by another method, such as ELISA or western blot.

Four. HIV antibody confirmation test

Protein blot test (WB), paper immunoassay (LIATEK HIV), radioimmunoassay (RIPA) and immunofluorescence test (IFA). The commonly used confirmation test method in China is WB.

(1) westernblot (WB) is an experimental method widely used in the diagnosis of many infectious diseases. As far as the etiological diagnosis of HIV is concerned, the confirmation of HIV antibody is the first choice, and WB test results are often used as the "gold standard" to distinguish the advantages and disadvantages of other detection methods.

Confirm the test process:

There are HIV- 1/2 mixed type and single HIV- 1 or HIV-2 type. First, use HIV- 1/2 mixed reagent to detect, and if it is negative, report that HIV antibody is negative; If it is positive, report that HIV- 1 antibody is positive; If it does not meet the positive criteria, it is determined that the HIV antibody test result is uncertain. If there is a specific indicator band of HIV-2, HIV-2 immunoblotting reagent should be used for HIV-2 antibody confirmation test, and HIV-2 antibody is negative. If it is positive, it will be reported that HIV-2 antibody is serologically positive, and the sample will be sent to the national reference laboratory for nucleic acid sequence analysis.

The sensitivity of WB is generally not lower than that of the initial screening experiment, but its specificity is very high, mainly based on the separation, concentration and purification of different antigen components of HIV, and antibodies against different antigen components can be detected, so WB method can be used to identify the accuracy of the initial screening experiment. From the results of WB confirmation test, it can be seen that even if better quality reagents are selected, such as the third generation ELISA, false positives will still appear in the initial screening test, and accurate results can only be obtained through the confirmation test.

(2) immunofluorescence test (IFA)

IFA method is economical, simple and rapid, and has been recommended by FDA for the diagnosis of WB uncertain samples. However, expensive fluorescence microscope and trained technicians are needed, and the observation and interpretation results are easily influenced by subjective factors, so the results are not suitable for long-term preservation, and IFA is not suitable for development and application in general laboratories. There are two lines on the test paper. The upper part is the quality control line, also called the control line, and the lower part is called the detection line.

When testing, if only one of the above results is negative, if both results are positive,

If only one or all of the following items are invalid, a second interview is recommended.