The OneTouch Verio Level 4 (High) Control Solution is formulated to verify the accuracy of your OneTouch Verio family of blood glucose meters and test strips. By applying a drop of this solution to a test strip, you can confirm that both the meter and strips are functioning correctly, ensuring reliable blood glucose readings. Regular use is recommended, especially when opening a new vial of test strips or if you suspect the meter's performance may be compromised.