1. Mansoura Nephrology and Dialysis Unit (MNDU), Faculty of Medicine, Mansoura University, Mansoura, Egypt
2. Nephrology Unit, Mansoura Military Hospital, Mansoura, Egypt
3. El Minia Hemodialysis Center, El Minia, Egypt
4. Dialysis Unit, Abokeir Hospital, Alexandria, Egypt
5. Temy Alamdeed Dialysis Center, Dakahlyia, Egypt
6. Dialysis Unit, Alexandria Fever Hospital, Alexandria, Egypt
7. Dialysis Unit, Raas El Teen Hospital, Alexandria, Egypt