The Purpose of Mid-Upper Arm Circumference Measurement in Children
The primary aim of mid-upper arm circumference (MUAC) measurement in children is to assess nutritional status, particularly to identify moderate malnutrition, which is associated with increased mortality risk and serves as an important indicator when weight measurements are unreliable due to fluid retention or edema. 1
Key Purposes of MUAC Measurement
MUAC serves as an alternative anthropometric tool for assessing malnutrition in children affected by conditions that make weight measurements unreliable, such as edema, ascites, steroid treatment, or large solid tumors 1
MUAC measurements between 115-135 mm indicate moderate malnutrition, which is associated with an increased risk of mortality (adjusted OR of 1.73) in children with respiratory conditions 1
MUAC, when combined with triceps skin fold thickness, allows calculation of mid-arm fat and muscle area, providing valuable insight into body composition beyond what weight alone can indicate 1
MUAC is particularly useful in resource-limited settings due to its simplicity, speed, and ease of use compared to other anthropometric measurements 2, 3
MUAC helps identify children who require referral or closer monitoring in clinical settings, particularly those with respiratory conditions like pneumonia 1
Clinical Applications and Thresholds
For children with pneumonia, MUAC measurements between 115-135 mm indicate moderate malnutrition requiring consideration for referral or closer monitoring 1
In infants 6-12 months of age, a MUAC value ≤12.5 cm has been found to have maximum sensitivity (92.1%) and specificity (88.3%) for detecting protein-energy malnutrition 4
MUAC should be expressed in relation to reference standards, typically as percentiles or standard deviation scores, to properly interpret a child's nutritional status 1, 5
Serial MUAC measurements provide a dynamic picture of nutritional changes over time, making it valuable for monitoring nutritional recovery 1, 3
Advantages Over Other Measurements
MUAC may be a better indicator than weight for classification of acute malnutrition in children with fluid retention issues 1
Unlike weight-for-age measurements, which can be affected by fluid status, MUAC provides a more reliable assessment of actual tissue mass 1
MUAC is particularly valuable in emergency situations and field settings where more complex anthropometric equipment may not be available 2, 5
MUAC can be measured by trained healthcare providers using standardized techniques with minimal equipment 1
Limitations and Considerations
MUAC's sensitivity and specificity vary with age, suggesting it is not entirely age-independent, particularly in children under 5 years 6, 5
MUAC should be used alongside other nutritional assessment methods when possible, including clinical examination and laboratory indices 1
Measurement techniques should be standardized and performed by trained individuals to ensure accuracy and reliability 1
Different reference ranges and cut-offs exist for different populations and age groups, requiring careful interpretation 2, 5