Is creatinine of 11.4 dangerous?

Yes: If accurate, this is indicative of severe kidney disease. However, the elevate creatinine isn't the real issue--it is the inability to excrete potassium. An elevated potassium level can stop your heart--this is how "lethal injection" is accomplished.

Elevated creatinine: Elevated creatinine is ussually a sign of kidney disease, patient with high muscle mass may have higher level of creatinine than those with low muscle mass, a crush injury can cause elevated creanine. Patient with severe with kidney disease ( elevated creatinine) may need to be placed on dialysis.