The key difference between ELISA and Rapid test is that the ELISA (enzyme-linked immunosorbent assay) is a highly specific sophisticated plate based immunoassay technique while the rapid test is a quick, easy to perform, less sophisticated immune-based screening that utilizes the same technique of ELISA.
HIV tests detect the presence of human immunodeficiency virus ((HIV) that causes acquired immunodeficiency syndrome (AIDS). Different HIV antibody tests are available. Among them, ELISA, Western blot, and rapid HIV test are commonly employing in the lab. These tests are carried out at different levels based on the availability of equipment and other factors, etc.
What is ELISA?
ELISA stands for enzyme-linked immunosorbent assay. It is a plate-based assay technique. Further, it is an enzyme immunoassay useful to detect HIV antibodies. Here, ELISA detects HIV antibodies produced between 2nd and 12th weeks of post-infection. During ELISA, the antigens in the sample bind with the immobilized antibodies on a solid surface. Once immobilized, again the antigens form complexes with antibodies linked to enzymes. Then, these conjugated enzymes incubate with the respective substrate.
Accordingly, the enzyme-substrate reaction produces a measurable coloured product. By measuring the amount of the product, it is possible to quantify the amount of antigens present in the sample. Therefore, ELISA is a very specific and sophisticated technique that requires the attention of well-skilled technicians. It is also a time-consuming process with a requirement of advanced equipment. There are several types of ELISA tests; namely, sandwich ELISA, direct ELISA and indirect ELISA. In all methods, the antigen-antibody interaction is the important detection element.
What is Rapid Test?
The rapid test is a preliminary immune-based screening test that utilizes the same technique of ELISA. The methodology is rapid and requires less sophisticated equipment in comparison to ELISA. Therefore, this method is popular in countries with limited resources. Compared to ELISA, rapid tests are less specific. Moreover, rapid tests are based on agglutination, immuno-dot, immuno-filtration, and immuno-chromatography.
Moreover, rapid test is a quick and easy to perform technique within a time period of 10 to 120 minutes. Therefore, this requires limited or no additional equipment. Furthermore, since it is a simple test to perform, it does not require well-skilled technicians. Also, rapid tests are designed to conduct emergency testing with a limited number of samples in smaller laboratories. Therefore, rapid tests are more economical than ELISA tests.
What are the Similarities Between ELISA and Rapid Test?
- Both ELISA and rapid test are diagnostic tools.
- They are tests to diagnose HIV.
- Also, both types function under molecular biological techniques.
What is the Difference Between ELISA and Rapid Test?
ELISA is a very sensitive and very sophisticated method that detects the presence of antigen and antibody in our blood. On the other hand, a rapid test is a quick, less sophisticated, and less sensitive method that also detects the presence of an antigen in our serum. Therefore, this is the key difference between ELISA and rapid test.
Furthermore, ELISA requires skilled personnel and sophisticated equipment to perform. On the other hand, the rapid test does not require skilled personnel and sophisticated equipment. Thus, it is another difference between ELISA and rapid test. Moreover, a further difference between ELISA and rapid test is that ELISA is time-consuming while rapid test is a quicker method that can be done within half an hour.
Below infographic on the difference between ELISA and Rapid test tabulates all these differences .
Summary – ELISA vs Rapid Test
To detect the HIV infection, several methods are available. Among them, ELISA and rapid test are two methods. The difference between ELISA and rapid test is that the ELISA is a highly specific and highly sensitive method which requires well-trained personnel and sophisticated equipment. On the other hand, a rapid test is a quick method which is less specific and less sophisticated. Furthermore, the rapid test does not need sophisticated equipment too. Moreover, the rapid test is easy to perform within a few minutes. Hence, it is not time-consuming as ELISA.
1. “Comprehensive, up-to-Date Information on HIV/AIDS Treatment and Prevention from the University of California San Francisco.” HIV Transmission and Prevention in Adolescents. Available here
2. “Simple / Rapid Tests.” World Health Organization, World Health Organization, 27 June 2014. Available here