Can donated blood be used to test for HIV?

The percentage of people who have successfully tested positive for AIDS in our country among those who have donated blood is 99.97%. Although this 0.03% failure rate is considered an "improbable event" in terms of probability theory, if this 0.03% probability event really happens, then the problem will be very serious. So, can blood donations be used to test for AIDS?

HIV Ab Window Period

Theoretically, HIV antibodies will appear when the human body is first infected with the AIDS virus, but the concentration at that time is extremely low, which is beyond the range of commonly used detection methods.

When the human body is infected with HIV for about 1.5 weeks, the binuclear sandwich method (commonly known as the "gold standard method") can be used for testing, but at this time, due to the low antibody concentration, there is a certain error in the test. When the human body is infected with HIV for 14 to 28 days, most detection methods including enzyme-linked method and binuclear sandwich method can obtain quite accurate results. When the human body is infected with HIV for 42 days, that is, about 6 weeks, the concentration of human HIV antibodies reaches its peak and then slowly decreases.

HIV Ag Window Period

Viral antigen testing is a more accurate method than antibody testing and can obtain quantitative results. As shown in the figure above, HIV Ag can reach its peak in about 4 weeks, and reliable results can be obtained one week earlier than HIV antibody.

However, since the level of HIV antigen in the human body decreases rapidly after reaching its peak, it will drop below the detectable level in about 6 weeks. Therefore, HIV antigen testing is mostly used for scientific research analysis rather than clinical use.

With the continuous development of HIV testing technology, the HIV window period can be shortened to 14 to 21 days for the widely used third-generation binuclear sandwich method, enzyme-linked method, and chemiluminescence method. In this regard, the World Health Organization (WHO) clearly stated that the HIV window period is 14 to 21 days.

In summary, we can conclude that there is a window period during which HIV cannot be detected by conventional means.

Conclusion:

We do not recommend using free blood donations to test for HIV. Currently, the Centers for Disease Control and Prevention (CDC) in all provinces and cities can test for HIV, and they do a very good job of protecting the privacy of testers. This is protected by law, so you can rest assured. In addition, there are many private testing agencies that provide anonymous testing services. If you still have doubts, you can also contact these testing agencies.