Is it true that using spirit (alcohol) before pricking for a blood glucose test can interfere with test accuracy?

Using Alcohol (Spirit) Before Blood Glucose Testing

Applying alcohol (spirit) before pricking for blood glucose testing does not interfere with test accuracy and is actually recommended for proper hygiene.

Effect of Alcohol on Blood Glucose Readings

Proper Use of Alcohol for Skin Preparation

• Alcohol-based skin preparation is a standard practice before capillary blood sampling for glucose testing 1
• Using alcohol (spirit) to clean the finger before pricking helps remove contaminants that could potentially affect glucose readings
• The key is to allow the alcohol to completely dry before pricking, which prevents any direct interference with the test 1

Scientific Evidence on Alcohol Use

• Research shows that properly applied and dried alcohol does not affect the accuracy of blood glucose readings 2
• In a study of 34 subjects, fingers cleaned with alcohol-based sanitizers showed no significant difference in glucose readings compared to control fingers cleaned with soap and water 2
• The alcohol itself does not interfere with glucose oxidase reactions used in most glucose meters when used correctly 2

Potential Interferences with Blood Glucose Testing

Actual Causes of Inaccurate Readings

• Operator-related errors are more significant sources of error than instrument-related errors 1
• Common technique errors include:
  • Improper calibration of glucose meters
  • Poor hand washing (not removing food residue or contaminants)
  • Dirty meters
  • Improper storage of test strips (exposure to humidity or temperature) 1

Substances That Can Affect Readings

• Certain drugs can affect accuracy of some meters, including:
  • Ascorbic acid (vitamin C)
  • Acetaminophen
  • Dopamine
  • Mannitol 1, 3
• Physiological factors that can affect readings:
  • Low hematocrit (can falsely increase readings)
  • Abnormal oxygen levels
  • Certain medical conditions 4, 5

Best Practices for Blood Glucose Testing

Recommended Procedure

1. Wash hands with soap and water when possible
2. If soap and water are unavailable, alcohol-based cleaners are an acceptable alternative
3. Allow the alcohol to completely dry before pricking
4. Ensure the first drop of blood is wiped away if there's visible contamination
5. Use the second drop of blood for testing 1

Important Considerations

• Glucose meters are less reliable in lower ranges of glycemia and may overestimate true glucose values in high glycemic ranges 1
• Alternative site testing (forearm, thigh) may lead to false results after eating, exercising, or with insulin treatment compared to fingertip testing 1
• For rapidly changing blood glucose levels, fingertip testing is preferred 1

Conclusion

The concern about alcohol (spirit) interfering with blood glucose readings is unfounded when proper technique is used. The key is ensuring the alcohol completely dries before pricking. In fact, cleaning the finger with alcohol before testing is part of standard recommended practice to ensure accurate readings by removing potential contaminants.