In the ongoing global effort to end the HIV epidemic, index testing has emerged as a key strategy in finding undiagnosed cases and linking them to treatment. Unlike broad-based testing campaigns that often target the general population, index testing index testing takes a more focused approach by tracing the sexual or needle-sharing partners, and biological children, of people who have already tested positive for HIV. It is a method rooted in both science and social engagement—designed to identify HIV-positive individuals who may otherwise remain undiagnosed.

What is Index Testing?

Index testing is also referred to as partner notification services (PNS) or contact tracing for HIV. In this approach, individuals who have tested positive for HIV—known as index clients—are asked to provide a list of people they may have exposed to HIV. These typically include:

Sexual partners (current and past)

Needle-sharing partners

Biological children

Spouses or cohabiting partners

Once these contacts are identified, healthcare providers or trained outreach workers discreetly contact them, offer HIV counseling, and recommend testing. The goal is to reach individuals who may not otherwise seek testing on their own but are at high risk due to known exposure.

Types of Index Testing Approaches

There are several methods used in index testing programs:

Passive Referral
The index client is encouraged to inform their partners and ask them to visit a testing site for HIV screening. This method depends on the initiative and willingness of the index client.

Contract Referral
The index client agrees to inform their partners within a specific time frame. If they fail to do so, a healthcare worker will follow up directly.

Provider Referral
Healthcare workers directly contact the partners and offer testing services without waiting for the index client to act first. This approach is often the most effective but requires trained staff and strict confidentiality.

Dual Referral
The index client and the healthcare provider jointly approach the partner to disclose the HIV status and offer testing.

These different methods offer flexibility in how sensitive conversations and actions are handled, aiming to balance effectiveness with ethical considerations.

Why is Index Testing Important?

Index testing has proven to be a high-yield strategy in HIV testing services. Here’s why:

Higher Positivity Rate: Compared to general population testing, index testing often identifies HIV-positive individuals at significantly higher rates, particularly in hard-to-reach populations.

Timely Linkage to Care: Early identification allows for immediate linkage to antiretroviral therapy (ART), reducing the chance of HIV-related complications and transmission.

Resource Efficiency: It is more cost-effective to target testing efforts toward people at known risk than to screen large, low-risk populations.

Helps Break the Chain: By identifying and treating both index clients and their contacts, the cycle of transmission is interrupted.

In countries with high HIV burden, such as in sub-Saharan Africa, index testing has dramatically improved HIV detection rates among partners and children of known PLHIV.

Index Testing in Global HIV Programs

The U. S. President’s Emergency Plan for AIDS Relief (PEPFAR) and the World Health Organization (WHO) have emphasized index testing as a core strategy in their HIV programs. Several African countries, including Kenya, Uganda, Nigeria, and South Africa, have adopted national index testing models as part of their routine services.

In many of these settings, trained community health workers or peer navigators are deployed to assist with partner notification and follow-up testing. Mobile health technologies and home-based testing kits are also being used to increase reach, particularly in rural or underserved regions.

Ethical and Human Rights Considerations

While index testing can be effective, it also raises ethical concerns, especially regarding privacy, consent, and the risk of stigma or violence:

Informed Consent: Index clients must provide voluntary, informed consent before their contacts are approached.

Confidentiality: The identity of the index client should not be disclosed to partners, unless explicitly permitted.

Risk of Gender-Based Violence: In certain contexts, disclosure of HIV status can put individuals—especially women—at risk of domestic abuse or abandonment.

Stigma and Discrimination: Fear of being stigmatized may prevent people from naming contacts or seeking testing themselves.

To address these issues, organizations implementing index testing programs must ensure training, monitoring, and ethical safeguards are in place. Confidentiality protocols, client-centered communication, and referral to support services (including gender-based violence resources) are critical components.

Challenges in Implementing Index Testing

Despite its advantages, several challenges can hinder the effective rollout of index testing programs:

Stigma and Fear
Cultural norms and social stigma can discourage individuals from disclosing their HIV status or providing information about partners.

Limited Human resources
In resource-constrained settings, there may be a shortage of trained staff to conduct partner tracing and follow-up.

Poor Data Systems
Inadequate tracking and monitoring systems can result in lost contacts or missed opportunities for testing.

Low Uptake Among Key Populations

Groups such as men who have sex with men (MSM), sex workers, and people who inject drugs may be reluctant to engage with formal health services due to fear of legal or social repercussions.

Overcoming these barriers requires investment in community engagement, digital health solutions, and the integration of index testing into broader HIV prevention efforts.

Innovations in Index Testing

Several innovations are helping to improve index testing outcomes:

HIV Self-Testing: Discreet and easy-to-use self-testing kits can be distributed to partners who are reluctant to visit a clinic.

mHealth Tools: Mobile apps and SMS-based systems are being used to manage referrals, reminders, and follow-ups.

Community-Based Testing: Taking services into the community—in homes, workplaces, or schools—improves access and comfort.

Integrated Services: Combining index testing with sexual and reproductive health services encourages more comprehensive care.

These approaches make index testing more responsive to the needs of diverse populations.

Conclusion: A Strategic Tool in HIV Control

Index testing is more than just a case-finding method—it is a strategic public health tool that saves lives, prevents new infections, and supports people living with HIV. When implemented ethically and effectively, index testing bridges gaps in diagnosis and treatment that traditional methods often miss.

For national programs and global health agencies aiming to reach the UNAIDS 95-95-95 goals (95% diagnosed, 95% on treatment, and 95% virally suppressed), index testing is essential. But success depends not just on protocols and numbers—it requires compassion, trust, community involvement, and a firm commitment to protecting human rights.

As the global fight against HIV continues, index testing remains a powerful weapon—provided it is wielded wisely.