What are the methods for self-testing for HIV?
Sep 13, 2022
Source: Cainiu Health
Dr. Yang Ziqi
Introduction
The primary method of HIV self-testing involves using HIV test strips, with commonly used types including colloidal gold test strips and oral fluid test strips. If the self-test result is positive, it is recommended to promptly visit a qualified medical institution for confirmatory testing. If the result is negative, retesting after the window period is advised, or one may directly go to a medical facility for professional testing.
Generally, HIV self-testing primarily involves the use of rapid HIV test strips. The most common types include colloidal gold-based test strips and oral fluid (saliva) test strips. A detailed explanation follows:
1. Colloidal Gold-Based Test Strip
A single drop of blood is typically collected from the fingertip or another suitable site and applied to the sample application well of the test strip. After waiting for a specified period, the result is interpreted based on color development. The test strip contains reagents that specifically bind to HIV antibodies or antigens, producing visible lines through a colorimetric reaction. If two red lines appear—the test line (T) and the control line (C)—the result is considered positive, regardless of line intensity, indicating possible HIV infection. If only the control line appears and the test line remains invisible, the result is negative, suggesting no HIV infection. If the control line fails to appear—regardless of whether the test line is visible—the test is invalid and must be repeated.
2. Oral Fluid (Saliva) Test Strip
A specialized oral fluid collection device is gently rubbed between the gums and inner cheek to collect saliva. The device is then placed into a tube containing buffer solution, and the resulting liquid is dispensed onto the test strip for analysis. As with the colloidal gold method, two red lines indicate a positive result; one red line (the control line only) indicates a negative result; and absence of the control line signifies an invalid test.
It is important to note that self-testing has inherent limitations and may yield false-positive or false-negative results. If the self-test result is positive, individuals should promptly seek confirmatory testing at a qualified healthcare facility. If the result is negative but there has been recent high-risk exposure and suspicion of infection remains high, retesting after the window period—or immediate professional testing at a healthcare facility—is strongly recommended.
