Ramon Estrada, who was serving 10 years in prison, died on April 5.
The University of Utah Health Care, which provides such services for the inmates at Utah prisons, revealed the new information after an investigation was carried out.
Two technicians at one of the dialysis clinics had switched shifts in early April, but the technician who was supposed to report for work at the prison forgot about the switch and missed the appointments, said University of Utah Health Care system spokeswoman Kathy Wilets.
Estrada, 62, died due to a heart attack following a kidney failure that was a direct cause of not receiving dialysis, a task of removing waste and excess water from the blood.
The death of Estrada is still being investigated by state correction officials.