Glucose control solution is a liquid mixture designed to verify the performance of a blood glucose meter and its test strips. This specialized fluid contains a known amount of glucose, buffers, and stabilizers, allowing it to mimic a blood sample. The primary function is to serve as a quality control check, ensuring the monitoring system is functioning accurately before measuring actual blood sugar levels. A successful control test confirms the meter and strips are working correctly.
Why and When to Perform a Control Test
Conducting a control test is necessary under several specific circumstances. You should perform a control test immediately when using a new blood glucose meter to establish its baseline accuracy. A test is also required when opening a new vial or package of test strips, ensuring the new batch has not been compromised.
A control test is also warranted if you suspect the meter or strips are giving inaccurate results. This includes situations where a blood glucose reading seems unexpectedly high or low and does not align with how you are feeling physically. Furthermore, if the meter has been dropped, damaged, or exposed to extreme environmental conditions like high heat, cold, or humidity, a control check should be performed to rule out a malfunction.
Step-by-Step Procedure for Testing
The control test procedure closely mirrors a standard blood glucose test, beginning with necessary preparations. First, gather all supplies, including your blood glucose meter, a test strip, and the correct control solution, which must be specifically matched to your meter brand. Before opening the solution, confirm both the control solution bottle and the test strip vial are within their expiration dates. Control solution typically expires 90 days after being opened, so you should write the opening date on the bottle.
To begin the test, gently invert or mix the control solution bottle a few times to ensure the components are evenly distributed, avoiding vigorous shaking. Insert a test strip into the meter, which will prompt the device to turn on. Follow your device’s instruction manual, as many meters have a specific setting or coding step for a control test to ensure the meter recognizes the sample as control solution and not blood.
Next, dispense a drop of the control solution onto a clean, non-absorbent surface, such as the cap of the bottle. It is best practice to first squeeze out a drop onto a tissue and discard it, then use the second, fresh drop for the test. Touch the tip of the inserted test strip to the second drop of control solution, allowing the strip to wick up the fluid until the meter starts its countdown. Wait for the numerical result to appear on the meter’s display.
Interpreting Control Test Results
Once the control test is complete, compare the displayed number to the acceptable range established by the manufacturer. This acceptable range is typically printed on the label of the test strip vial or on the control solution packaging. Locate the range that corresponds to the specific level of control solution you used, as manufacturers often provide “Level 1” (low) or “Level 2” (high) solutions.
If the result falls within this specified range, the meter and test strips are confirmed to be working accurately, and you may proceed with blood glucose testing. Conversely, if the result is outside of the acceptable range, it indicates a potential problem with the meter, the test strips, or the solution itself.
In this scenario, first re-read the instructions and repeat the control test with a new test strip to rule out a procedural error. If the second control test also yields a result outside the range, check that the control solution is not expired or contaminated and that the test strip vial was capped properly. Should the system continue to fail the control test, stop using the meter for blood glucose testing and contact the manufacturer for technical support.