Accu-Chek Nano Owner's Booklet page 26

Troubleshooting Checks
6. Did you follow all of the testing instructions?
7. If you are still unsure of the problem ...
24
Action
Read Chapter 2, Control Testing, and test again. If you
still have problems, contact the ACCU‑CHEK Customer
Care Service Center at 1‑800‑858‑8072.
Repeat the control test with a new test strip. If you
still have problems, contact the ACCU‑CHEK Customer
Care Service Center at 1‑800‑858‑8072.