Rhabdomyolysis may lead to acute kidney injury following deposition of myoglobin in renal tubules. Although high-flux dialysis membranes may remove a substantial amount of myoglobin from plasma, this may still not be sufficient to prevent renal damage. We tested a new polymer sorbent, X-Sorb, in vitro to determine its potential to clear myoglobin from solutions. Normal saline or human serum in which myoglobin was dissolved was perfused by a peristaltic pump through a column packed with the sorbent. After a 4-hour perfusion, the myoglobin level in normal saline fell from 200,000 ng/ml to virtually undetectable (<780 ng/ml). Perfusion through the sorbent was then found to lower concentrations of dissolved myoglobin in 3 different 110-ml samples of human serum consistently by > 90% over 4 hours. X-Sorb appears to be an effective sorbent for myoglobin and warrants a trial in vivo to determine whether it is equally effective and safe.