WFH as % of median reference value is calculated this way:
  
    
      
        
          W
          F
          H
        
        =
        
          
            
              weight of a given child
            
            
              median weight for a given child of that height
            
          
        
        ×
        100
      
    
    {\displaystyle \mathrm {WFH} ={\frac {\mbox{weight of a given child}}{\mbox{median weight for a given child of that height}}}\times 100}
  Cutoff points may vary, but <80% (close to −2 Z-score) is often used.
Adults:
Body Mass Index (BMI) is the quotient between weight and height squared (kg/m2). An individual with a BMI < 18.5 is regarded as a case of wasting. Percent of body weight lost (At Tufts, an unintentional loss of 6% or more in 6 months is regarded as wasting)

Treatment and prevention
Antiretrovirals and anabolic steroids have been used to treat HIV wasting syndrome. Additionally, an increase in protein-rich foods such as peanut butter and legumes (dried beans and peas) can assist in controlling the loss of muscle mass. See also
Anorexia
Atrophy
Cachexia
Superior mesenteric artery syndrome
Weight loss

References
External links

Chronic Wasting Disease and Potential Transmission to Humans, Center for Disease Control and Prevention
Unintentional Weight Loss/Wasting, Tufts University Nutrition/Infection Unit