The control solution has a known amount of glucose. This range is printed on the test strip vial. Use only OneTouch Verio control solution, Level 3 (mid) or Level 4 (high) with your OneTouch Verio IQ meter. When you do a control solution check and the results on the glucose meter match the expected range of either Level 3 (mid) or Level 4 (high) on the test strip vial, you know that the meter is working correctly.