Using measuring tapes to measure arm circumference is the most inexpensive and reliable factor in diagnosing malnutrition than weight-based measurements.

Adam Levine, emergency medicine physician at the Rhode Island Hospital in the US, said, "Using a measuring tape to measure arm circumference is the most reliable factor in diagnosing malnutrition. Measuring tapes are inexpensive and readily available in resource-limited environments. Dehydration lowers a child’s weight, using weight-based assessments in children introduced with diarrhea may be misleading. When children are re-hydrated and returned to a stable, pre-illness weight, they may still suffer from acute malnutrition."
Researchers studied the clients of an urban hospital in Dhaka, Bangladesh. They analyzed 721 records of all children under 60 months of age who visited the hospital’s re-hydration unit with acute diarrhea. They found that 12-14% of children were misclassified with malnutrition using weight-based measures compared to only 1-2% who were measured by arm circumference.
The study has been published in the Journal of Nutrition.
Source-Medindia