(HealthDay News) -- A blood glucose meter is key to helping a diabetic person keep blood sugar under control.

But the meter is worthless if it doesn't function properly. The American Diabetes Association says the accuracy of these lifesaving gadgets can be compromised if:

• The meter is dirty.
• The meter or test strips aren't stored at room temperature.
• The test strips are too old.
• The meter isn't calibrated for the current set of test strips.
• The blood sample used is too small.