A groundbreaking international study validates a dual rapid test that can screen for two major infections simultaneously with exceptional accuracy.
HIV and syphilis are more than just serious sexually transmitted infections (STIs); they form a dangerous partnership. Having syphilis can increase the risk of both acquiring and transmitting HIV 1 . Furthermore, both infections can be passed from mother to child during pregnancy, leading to severe consequences like stillbirth, newborn death, or congenital syphilis 1 9 .
For years, screening for these diseases often required separate tests, involving different equipment, multiple visits, and longer wait times. This process can be a significant barrier, especially in remote or under-resourced areas. The World Health Organization (WHO) has championed the "dual elimination" of mother-to-child transmission of both HIV and syphilis, and integrated testing is a cornerstone of this strategy 1 6 .
Dual rapid tests meet the WHO's "ASSURED" criteria—they are Affordable, Sensitive, Specific, User-friendly, Rapid and robust, Equipment-free, and Deliverable to those who need them most 1 .
By combining two tests into one, they streamline screening, reduce costs, and make it easier for people to learn their status and get treatment quickly, sometimes in the same visit 9 .
Syphilis increases the risk of both acquiring and transmitting HIV, making combined screening crucial.
The test evaluated in this landmark study was the SD BIOLINE HIV/Syphilis Duo. It is a small, lateral flow device—similar to a home pregnancy test—but with two separate result windows.
Here's how it works: A small sample of blood is applied to the test. As the sample moves along the strip, it encounters recombinant antigens for both HIV and the syphilis bacterium (Treponema pallidum). If the person has antibodies to either infection, a visible line will appear in the corresponding window, providing a clear, visual result in approximately 20 minutes 1 . This design allows a healthcare worker to check for two infections from a single finger-prick.
A small blood sample is collected via finger-prick.
The blood sample is applied to the test device.
The sample moves along the strip, encountering recombinant antigens.
If antibodies are present, visible lines appear in the corresponding windows.
Clear visual results are available in approximately 20 minutes.
To ensure a new diagnostic test is reliable across different populations and settings, it must be rigorously evaluated. From 2012 to 2013, a major study was conducted across six countries: Ghana, Mexico, Laos, Togo, Kenya, and Myanmar 1 . This multisite approach was crucial for determining if the test would perform consistently worldwide.
The methodology was straightforward but thorough:
The findings, published in 2014, were exceptionally positive. The dual test demonstrated near-perfect accuracy across all the diverse sample sets.
| Country | Sensitivity | Specificity | Performance |
|---|---|---|---|
| Ghana | 100% | 100% |
|
| Togo | 100% | 100% |
|
| Myanmar | 98.84% | 99.37% |
|
| Kenya | 100% | 99.12% |
|
| Laos | 100% | 100% |
|
| Mexico | 100% | 100% |
|
Adapted from source data in 1
| Infection | Statistic | Value |
|---|---|---|
| HIV | True Positives | 99.91% |
| True Negatives | 99.67% | |
| Syphilis | True Positives | 99.67% |
| True Negatives | 99.72% |
The real-world impact of this technology is already being felt. In a 2023 Canadian study, the use of dual rapid tests in emergency departments, a correctional facility, and an Indigenous community allowed 85% of syphilis-positive patients to receive treatment on the same day 9 . This immediate intervention is crucial for cutting off chains of transmission and preventing tragic outcomes like congenital syphilis.
The WHO prequalified the first bundled set of three rapid tests for HIV, hepatitis B, and syphilis in July 2025. This "Determine™ Antenatal Care Panel" is a major step toward "triple elimination" of mother-to-child transmission of these three diseases 6 .
Meanwhile, innovation continues with tests like Chembio's DPP® Syphilis TnT Assay, which can detect both treponemal and non-treponemal antibodies, potentially identifying active syphilis infections in just 15 minutes 7 . The future points toward even more integrated multiplex tests that can screen for a panel of infections from a single sample, making preventive healthcare more efficient and accessible than ever before 3 .
The multisite evaluation of the SD BIOLINE HIV/Syphilis Duo test provided the robust evidence needed to confidently deploy this tool worldwide. By proving that a single, simple test can reliably detect two infections with exceptional accuracy, it opened the door to more integrated, patient-centered healthcare. As dual and triple tests become more widespread, they represent more than just a diagnostic advance—they are a smarter, more compassionate way to protect public health, one drop of blood at a time.