Self-Monitoring of Blood Glucose: Use First or Second Drop of Blood?

Capillary glucose concentrations were measured in two consecutive drops of blood in the following circumstances in 123 patients with diabetes: without washing hands, after exposing the hands to fruit, after washing the fruit-exposed hands, and during application of different amounts of external pressure around the finger. The results were compared with control measurements.  

The results showed that, not washing hands led to a difference in glucose concentration of ≥10% in the first and in the second drops of blood in 11% and 4% of the participants, respectively. In fruit-exposed fingers, these differences were found in 88% and 11% of the participants, respectively. Different external pressures led to ≥10% differences in glucose concentrations in 5-13% of the participants.  

From the results it was recommend washing the hands with soap and water, drying them, and using the first drop of blood for self-monitoring of blood glucose. If washing hands is not possible, and they are not visibly soiled or exposed to a sugar-containing product, it is acceptable to use the second drop of blood after wiping away the first drop. External pressure may lead to unreliable readings.  

Published online February 2, 2011, doi: 10.2337/dc10-1694 Diabetes Care February 2, 2011 DC_101694