Researchers developed a wearable pad that detects inflammation and cancer biomarkers in menstrual blood using smartphone analysis, enabling low-cost, non-invasive health monitoring at home.
(Nanowerk Spotlight) Blood tests offer some of the most reliable clinical insights, but the need for sterile instruments, trained staff, and controlled settings makes regular testing out of reach for many. This is especially true in gynecological health, where early signs of inflammation, hormonal disorders, or cancer are often missed due to infrequent screening. And while non-invasive alternatives like saliva and urine have been explored, they lack the molecular richness of blood.
Yet one biological fluid—produced regularly by roughly half the global population—has remained excluded from mainstream diagnostics: menstrual blood. Historically treated as medical waste, it has rarely been studied for its diagnostic value. Part of this exclusion stems from social stigma, but technical assumptions also played a role. Menstrual blood, once thought too contaminated or variable for serious analysis, has only recently begun to be reassessed in scientific literature. Proteomic studies now show that it contains hundreds of systemically relevant proteins, many of which correlate closely with those in venous blood.
Previous research has shown that menstrual blood can be used to measure indicators like glycated hemoglobin or detect human papillomavirus. But these studies required dried samples to be sent to labs for processing—an approach that undermines the potential for immediate, personal, and accessible health monitoring. Commercial efforts to integrate sensors into pads have existed, but their focus was narrow, limited to tracking pH or flow volume rather than generating clinically relevant biomarker data.
Against this backdrop, researchers at ETH Zurich and partner institutions have developed a wearable diagnostic platform embedded directly into sanitary pads, capable of detecting key disease biomarkers from unprocessed menstrual blood. This approach bypasses invasive sampling, laboratory processing, and specialized equipment, offering a new model for how gynecological and systemic health might be monitored passively, regularly, and with minimal effort.
In a study published in Advanced Science (“A Wearable In‐Pad Diagnostic for the Detection of Disease Biomarkers in Menstruation Blood”), the team describes MenstruAI—a low-cost, microfluidic sensor platform designed for integration into commercially available hygiene pads. The system uses lateral flow assays (LFAs) to detect clinically important proteins associated with inflammation, cancer, and reproductive disorders. Unlike most blood tests, it works without any preprocessing, dilution, or external instrumentation. Color changes on the paper-based strip provide a semi-quantitative result that can be interpreted by eye or read with a smartphone app powered by machine learning.
Concept of menstruation blood biosensor integrated into hygiene pads enabling direct naked-eye readable semi-quantitative analysis of biomarkers in unprocessed menstruation blood. The platform termed MenstruAI is designed to include infection/inflammation, cancer and endometriosis biomarkers based on an in-pad integrated lateral flow assay (LFA) platform with integrated volume control. (Image: Reprinted from DOI:, CC BY)
The MenstruAI platform targets three biomarkers with strong clinical relevance: C-reactive protein (CRP), carcinoembryonic antigen (CEA), and cancer antigen 125 (CA-125). CRP is a widely used marker of acute inflammation and chronic disease risk. CEA is often elevated in colorectal and other cancers, while CA-125 is used to monitor ovarian cancer and endometriosis. These biomarkers are present at low concentrations in healthy individuals, making them suitable for early detection of pathological changes.
To ensure compatibility with the unique properties of menstrual blood, the researchers designed the assays to function directly with whole, unprocessed samples. Red blood cells and coagulated material are filtered out by specialized membranes, while plasma flows through the assay strip. The use of antibody-coated gold nanoparticles produces visible lines whose intensity correlates with biomarker concentration. This approach eliminates the need for laboratory processing and provides results in a form that can be read by users without technical training.
The assays were validated in spiked samples of human serum, venous blood, and menstrual blood. All three showed strong performance across clinically relevant concentration ranges. The CEA test, for example, had a detection limit of 0.85 ng/mL and showed linear responses up to 500 ng/mL. CA-125 assays demonstrated sensitivity from 0 to 1000 U/mL, a range that covers both healthy and disease states. CRP detection presented an additional challenge due to the “hook effect,” a phenomenon that can cause high concentrations of analyte to produce weaker signals. To address this, the researchers combined two assay formats—sandwich and competitive—into a three-line system that maintained accuracy across a wide dynamic range from 0.15 to 500 μg/mL.
To house the sensors, two wearable prototypes were developed using soft, biocompatible silicone casings. One version employs a dissolvable membrane that releases a controlled volume of blood onto the assay after a set period. The second uses capillary microfluidics to move fluid through narrow channels based on pressure gradients, allowing for precise volume control. Both designs prevent over-saturation, maintain test integrity, and ensure comfort during daily activities.
User testing showed that the pads functioned under realistic conditions. Volunteers wore the device during menstruation for several hours, during which normal activity such as walking and sitting was performed. The sensors successfully sampled blood, activated the assays, and retained clear readouts. Comfort and usability were reported as equivalent to standard commercial pads.
Interpreting test results from colorimetric assays can be subjective, especially when dealing with multiple markers or borderline concentrations. To mitigate this, the team developed a smartphone app using a convolutional neural network trained to identify and interpret the assay lines. Users can take a picture of the used strip, and the app automatically detects the readout zone, classifies the biomarker lines, and quantifies their intensity. This is then matched to calibrated concentration ranges to deliver a semi-quantitative result. The app also stores previous results, enabling users to track trends over time or share data with healthcare providers.
Multiplexing was also demonstrated. A single test strip can be designed to detect multiple biomarkers simultaneously using either line-based or dot-based arrangements. Minimal cross-reactivity was observed, suggesting the platform could be expanded to include additional targets such as sexually transmitted infections or hormonal markers. The estimated production cost of the entire device—including the test strip and silicone casing—is around one dollar per unit, aligning with global affordability goals for point-of-care diagnostics.
The platform meets key criteria set out by the World Health Organization for diagnostic tools, including affordability, ease of use, and equipment-free operation. However, the authors note that further clinical validation is necessary. Large-scale studies are needed to assess variability in menstrual blood across individuals and cycles and to ensure consistent performance across a broader population.
While not intended to replace clinical tests, the device can serve as a first alert system, prompting users to seek medical advice when abnormal levels are detected. Its passive nature—functioning during ordinary pad use without any required action—positions it as a potential tool for regular, unobtrusive health surveillance.
The research marks a shift toward using menstrual blood not merely as a biological curiosity but as a diagnostic resource. By turning an often-discarded fluid into a platform for disease monitoring, MenstruAI may help reduce barriers to healthcare access and provide menstruating individuals with a more active role in tracking their health.
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