Spontaneous bleeding in a patient on enoxaparin with poor renal function

Creatinine-based equations are used as standard ways to estimate glomerular filtration rate and kidney function. Unfortunately, serum creatinine varies based on factors such as age, gender, and muscle mass. Overestimation of renal function by creatinine-based equations can be dangerous for renally dosed medications, such as enoxaparin. We present a patient who developed spontaneous bleeding on enoxaparin where kidney function was significantly overestimated by creatinine-based equations. The use of cystatin C levels, which are creatinine independent, can provide a better prediction of renal function.