A dialysis system includes: a blood filter; a dialysate pump connected to a dialysate portion of the blood filter; a blood pump connected to a blood portion of the blood filter, the blood pump including a diaphragm that is moved in cycles to pump the blood, the cycles having a flow period and a no-flow period; a patient access device in fluid communication with the blood portion of the blood filter, the no-flow period having a first characteristic of a property when the patient access device is lodged in a patient and a second characteristic of the property when the patient access device is dislodged from the patient; and a logic implementer configured to determine that the patient access device has been dislodged from the patient when the second characteristic of the parameter is detected.