Warning: an anemia outbreak due to chloramine exposure in a clean hemodialysis unit--an issue to be revisited.

In July 2004, an anemia outbreak was identified in our hemodialysis (HD) unit. The dialysate chloramine levels had risen from <0.1 mg/mL in May to 0.27 mg/mL in August 2004. Other parameters of water quality were within accepted standards. Hematocrit (Ht) and hemoglobin (Hb) returned to basal values after one month without changing recombinant human erythropoetin (rHuEpo) doses and with exchange of activated charcoal column. Chloramines (chlorine and ammonia) are used routinely to disinfect and sterilize potable water. High blood levels of chloramines are associated with hemolysis and rarely methemoglobinemia. Uremic patients have a decreased ability to withstand oxidative stress. It is postulated that their antioxidant capacity is reduced, yet the mechanism remains unclear. Patients on maintenance hemodialysis are vulnerable to chloramine toxicity if chloramines are inadequately removed from water.