The calculator in question is the ASPEN Diagnostic Criteria for Refeeding Syndrome. ASPEN stands for the American Society for Parenteral and Enteral Nutrition. This scoring system is used specifically in patients who are malnourished or at risk of malnutrition, and who are about to undergo refeeding, either orally, enterally, or parenterally. 

The clinical utility of the ASPEN Diagnostic Criteria for Refeeding Syndrome is to identify patients at risk of developing refeeding syndrome, a potentially fatal condition characterized by severe electrolyte and fluid shifts in malnourished patients as they receive artificial refeeding. Early identification of these patients allows for careful monitoring and adjustment of nutritional therapy to prevent the onset of the syndrome.

There are no specific exclusion criteria for the use of the ASPEN Diagnostic Criteria for Refeeding Syndrome. However, it is not applicable to patients who are not malnourished or at risk of malnutrition, or those not undergoing refeeding.

ASPEN diagnostic criteria for refeeding syndrome

# Criteria
 ## Decrease of serum potassium, phosphorus or magnesium by
A. 10-20%
B. 20-30%
C. > 30% and/or organ dysfunction

# Conditions
- A
- B
- C
- true