New Study Finds Widely Used Malaria Rapid Test May Be Failing Patients in Key Regions

A new international study has raised serious concerns about the reliability of the Abbott-Bioline malaria rapid diagnostic test, a tool used in many parts of the tropical world to quickly detect malaria infections. Researchers working in Southeast Asia found that this particular test is producing far too many false-negative results, prompting calls for its removal from the market in that region. With malaria still affecting millions globally each year, especially in remote communities, the stakes could not be higher.

The study, published in the Malaria Journal, was conducted by the Shoklo Malaria Research Unit (SMRU), part of Oxford University’s MORU Tropical Health Network. Their findings show that the Abbott-Bioline test correctly identified only 18% of Plasmodium falciparum infections and 44% of Plasmodium vivax infections in their field evaluations. These detection rates are dramatically lower than those of other rapid tests in use, and far below what is considered acceptable for frontline diagnostics.

The researchers observed that many of the positive results produced by the Abbott-Bioline test appeared as extremely faint lines, sometimes barely visible to trained medical staff. In challenging environments—like forested regions during monsoon season or clinics with poor lighting—these faint indicators can easily be missed, causing healthcare workers to incorrectly record a negative result.

This is especially troubling because rapid diagnostic tests (RDTs) are a crucial part of malaria control. They allow quick, near-home diagnosis in regions where laboratory testing is unavailable. When functioning properly, RDTs help ensure that patients receive timely treatment and reduce further transmission. A faulty test, however, can do the opposite. Being told “you don’t have malaria” when you actually do can delay treatment, worsen symptoms, and in the case of P. falciparum, even become life-threatening.

The SMRU study was conducted on the Thailand-Myanmar border between October 2024 and January 2025, an area where conflict and instability have already disrupted healthcare access. Until recently, this region was close to eliminating falciparum malaria. A faulty diagnostic tool could reverse progress and put vulnerable communities at greater risk.

To compare accuracy, researchers tested the Abbott-Bioline device alongside another WHO-approved rapid test as well as traditional microscopy, still considered the gold standard. In these comparisons, the Abbott-Bioline test consistently failed to detect confirmed infections. Based on these results, the study concludes that the test is not fit for purpose in its current form.

Abbott, the manufacturer, disputes the findings. The company reported that after reviewing the issues raised, they found the product to be performing as intended. They also engaged a WHO-qualified laboratory to conduct additional testing, which they say supported their conclusions. Abbott stated that any visible test line—no matter how faint—is considered a positive result according to the product’s labeling, and emphasized that they are exploring whether test-line intensity can be increased to make results clearer.

However, health experts argue that faint lines pose a real-world problem. As one consultant involved in malaria-surveillance studies in Nigeria, Uganda, and Benin explained, faint lines increase the risk of misinterpretation and recording errors. When health workers must log results for surveillance and planning, even small inaccuracies can distort national malaria statistics, affecting funding, resource allocation, and policy decisions.

In fact, a separate study involving Abbott’s test and another brand—First Response—found that certain rapid tests showed higher rates of result changes over time, meaning that what appears faint today might disappear tomorrow, complicating audits and data verification.

The World Health Organization (WHO) has been aware of reports of false negatives and faint lines since August 2024. In March 2025, WHO issued a public notice addressing concerns and advising proper test use, while also calling for more incident reporting. They later sent a detailed technical note to regional advisers. WHO has worked with Abbott Diagnostics Korea, which manufactures the tests used in Asia and South America, to investigate. A site inspection did not find sufficient cause to delist the product. WHO is now awaiting new studies from the manufacturer—due by December—before deciding whether further action is necessary.

Interestingly, Abbott-Bioline tests have shown better performance in parts of Africa, suggesting that geographical or strain-specific factors may influence accuracy. However, the problems reported in Southeast Asia appear significant enough that researchers fear thousands of infections could be missed if the test continues to be used widely.

This has serious implications. Malaria elimination efforts depend heavily on accurate detection, especially in regions where transmission is already low. Missing even a small percentage of cases can allow the disease to linger undetected in the community. For individuals living in remote locations, where access to clinics and hospitals is already limited, unreliable diagnostics add yet another layer of risk.

The test’s ability to differentiate P. falciparum from non-falciparum infections—one of its advertised strengths—also becomes irrelevant if the test cannot reliably detect either parasite. Abbott’s website continues to promote the test as suited for regions where multiple malaria species circulate, but recent findings challenge that claim.

Extra Context About Malaria Rapid Diagnostic Tests (RDTs)

Since this news raises big questions about malaria testing, it’s helpful to understand how RDTs work and what can affect their performance.

RDTs detect specific malaria antigens in a drop of blood applied to a test strip. Their advantages include speed, low cost, and ease of use. They do not require electricity, expensive equipment, or highly trained technicians. But several factors can compromise an RDT’s accuracy:

1. Parasite density
If the number of parasites in the blood is very low, the test may fail to detect antigens. This is common in early infections and in regions approaching elimination, where people tend to carry fewer parasites.

2. Genetic variations
Some malaria parasites, especially Plasmodium falciparum, can have HRP2 gene deletions, making HRP2-based tests ineffective. This problem has been rising in several countries.

3. Storage conditions
RDTs are sensitive to heat and humidity. Poor storage during transport or at clinics can reduce their reliability.

4. Faint line visibility
Even when a test technically detects antigens, the line may be too faint for busy or undertrained staff to interpret correctly. This becomes a serious issue in dimly lit rural environments.

5. Manufacturing differences between batches
Variability between production batches can cause sudden declines in accuracy if quality issues arise.

Because of these factors, malaria experts often stress the need for strong quality-control programs, regular field validation, and backup diagnostic options when RDT results don’t match symptoms.

Why This Controversy Matters for Global Health

Malaria remains a major public-health concern, with millions of infections every year. In many parts of Asia, Africa, and South America, RDTs are the primary diagnostic tool available. When a widely used test underperforms, the consequences ripple across communities, data systems, and national malaria-control strategies.

Reliable diagnostics are essential for:

• early treatment and prevention of severe disease
• reducing transmission
• tracking outbreaks
• evaluating progress toward elimination
• guiding policy and funding decisions

If even one major brand becomes unreliable, countries may unknowingly base decisions on inaccurate data, ultimately slowing down global efforts to control and eliminate malaria.

The coming months will be important as WHO reviews new evidence and decides whether the Abbott-Bioline RDT should remain approved for use. For now, researchers in Southeast Asia are urging caution and calling for alternative tests with better performance.

Research Reference:
Investigating the Abbott-Bioline malaria antigen Pf/Pv rapid diagnostic test – Malaria Journal (2025)
https://doi.org/10.1186/s12936-025-05577-2