A Portable Digital MUAC Bracelet for Assessing the Acute Malnutrition Degree of Children

Acute malnutrition remains a significant concern among children of low-income countries, arising from inadequate nutrient intake and resulting in severe implications such as reduced immunity and, in more critical grades, mortality. In this work, we propose a new screening tool composed of a small-size digital bracelet capable of measuring mid-upper-arm circumference (MUAC) and an Android-based application to rapidly assess the acute malnutrition of children in low-income countries. The core of the digital MUAC bracelet is a STM32 microcontroller connected to a magnetic sensor for precise measurements of the tape length arranged around the child’s arm. This instrument facilitates mass-screening by local healthcare operators. The measured MUAC value is automatically transmitted via Bluetooth to the Android application for streamlined data collection and storage. The digital MUAC bracelet was initially calibrated at a private clinic in Italy and then field-tested in Uganda, demonstrating a precision of -0.8 mm and an accuracy of 3.5 mm. From our mass screenings, 4% of children were acutely malnourished with 2% affected by severe malnutrition. Local staff confirmed the instrument's effectiveness, highlighting its advantages over traditional methods based on manual MUAC tapes and paper-based data transcription.