Mid-Upper Arm Circumference (MUAC) is a measurement of the upper arm’s circumference. It serves as a rapid method for assessing an individual’s nutritional status. This measurement is relevant for identifying malnutrition, especially in children aged 6 to 59 months and pregnant women.
How Mid-Upper Arm Circumference is Measured
Measuring Mid-Upper Arm Circumference involves a standardized technique. A specialized MUAC tape, often color-coded, is used for this assessment. The measurement is taken on the left arm, which should be relaxed and hanging by the person’s side.
To find the correct anatomical landmark, the midpoint between the tip of the shoulder (acromion) and the tip of the elbow (olecranon process) is identified. The midpoint can be marked with a pen. The MUAC tape is then wrapped around the arm at this midpoint, ensuring it lies flat against the skin without being too tight or too loose. The measurement is read to the nearest millimeter from the designated window on the tape.
Why Mid-Upper Arm Circumference is Used
MUAC is a widely adopted tool. It is a quick, low-cost, and non-invasive screening method, suitable for use in resource-limited environments or emergencies. Its simplicity allows community health workers and trained parents or caregivers to perform the measurement.
This measurement is effective for identifying individuals at risk of malnutrition, particularly severe acute malnutrition (SAM) in children, because it correlates well with mortality risk. MUAC measures muscle and fat mass, which are indicators of overall nutritional status. It is less affected by fluid accumulation, such as nutritional edema, compared to other anthropometric measures like weight-for-height, making it a reliable indicator.
Interpreting Mid-Upper Arm Circumference Results
MUAC measurements are interpreted using specific thresholds, displayed as color-coded zones on the tape. These zones provide a quick visual indication of nutritional status. A green zone indicates that the individual is well-nourished.
A measurement falling within the yellow zone suggests moderate acute malnutrition or risk of malnutrition. For children, this translates to a MUAC between 115 mm and less than 125 mm. In such cases, referral for further assessment or supplementary feeding programs may be recommended.
The red zone signifies severe acute malnutrition, indicating a need for immediate intervention and treatment. For children aged 6 to 59 months, a MUAC measurement less than 115 mm falls into this category. Individuals in the red zone are at increased risk of adverse health outcomes and should be referred to a health or nutrition center for therapeutic feeding and medical attention.