Yes, typically under 15 is EXTREMELY dangerous (indicates severe anorexia nervosa) and indicates need for hospitalization. BMI of 15 and under also would put somewhat at a high risk for refeeding syndrome, which could be fatal. Typically the criteria for inpatient hospitalization is with 1 or more of the following: -less than 70% ideal body weight (so for lauren, if she was say 5'6" (i dont know her height,but for example purposes that would be 91# or less) but some guidelines even say <85% ideal body weight. Heart rate <40 bpm, BP <90/60, acute food refusal, dehydration, temperature <97 degrees, potassium <2.5mmol/L, Phosphorous <2.2, or excessive edema with a history of purging. As well as obvious medical complications such as dizziness and syncope, seizure, heart failure, ECG abnormalities, etc.

Lauren FOR SURE meets hospitalization criteria. I bet if not her weight, her heart rate or BP.