HIV ELISA Test. Type Of ELISA To Detect HIV
HIV ELISA Test
What is the ELISA test? The ELISA test is the most basic test for HIV (human immunodeficiency virus). It stands for ‘enzyme-linked immunosorbent assay’. This method detects HIV antibodies from a patient’s blood sample. The ELISA test checks for particular proteins that the human body produces in response to HIV infection. It is also the first widely used procedure in checking for HIV.
What type of ELISA is used to detect HIV?
There are different types of HIV ELISA tests. Any of these types can detect the virus; however, they have different methods in terms of the enzymes used. These are as follows:
- Direct ELISA
- Indirect ELISA
- Sandwich ELISA
- Competitive ELISA
Direct ELISA detects HIV much faster than other methods. It is mainly because direct ELISA has fewer steps compared to the rest. Its disadvantage, however, is its unspecified antigen immobilization. Furthermore, it reduces assay sensitivity.
Compared to direct ELISA, indirect ELISA has a lengthier procedure for detecting HIV infection. However, this technique is best for determining the total amount of HIV antibody concentration in blood samples.
On the other hand, the sandwich ELISA test has a high sensitivity rate compared to direct and indirect ELISA. Aside from that advantage, this technique is also highly applicable in the analysis of complex blood samples.
Also called a blocking ELISA, the competitive ELISA is probably the most complex among the mentioned techniques. It is more robust and more consistent; however, it has limitations. This technique is best for detecting small antigens.
ELISA HIV Test Procedure
The ELISA test is the most basic form of HIV testing. Its procedures are as follows:
- A medical professional will collect a blood sample from a person. The blood is extracted from a vein.
- The blood sample is then processed to get the serum.
- Once the serum is available, it is applied to the ELISA plate that contains the antigens.
- The sample is then treated with an enzyme, which is attached to the antibodies of the antigens. Afterwards, a chemical reaction occurs that results in a change of color. If this change of color takes place, the result is positive for HIV.
How accurate is the ELISA test?
Despite the controversies surrounding the ELISA test, it is one of the most accurate tests for HIV detection. There are instances that individuals receive a positive result when they do not have HIV at all. However, the ELISA test can provide an accurate negative result.
What are other HIV tests?
Aside from the ELISA test, there are other HIV tests that you can participate in. These are as follows:
- Western blot test
- Antigen or antibody tests
- NAT (Nucleic Acid Test)
If you receive a positive result after an ELISA test, you will take another test to confirm the result. If the same positive result comes back, you have HIV, and immediate treatment with antiretroviral drugs is necessary. If the result is negative, HIV antibodies are not detected on the blood sample, but preventive measures are a must to avoid future HIV acquisition.