Washing hands recommended before blood glucose testing
MedWire News: Study findings confirm those from previous research that advocate hand washing before blood glucose testing to optimize result accuracy in patients with diabetes.
The authors suggest that use of the first drop of blood for testing is advisable after hand washing, but say that using the second drop may improve accuracy if hand washing is not possible, as long as the hands are not visibly stained or sugar exposed.
Johanna Hortensius (Isala Clinics, Zwolle, The Netherlands) and colleagues recruited 123 patients with diabetes to determine whether blood glucose levels obtained by testing the first and second drop of blood on finger prick testing varied by 10% or more versus control measures under different testing conditions.
They measured capillary blood glucose levels in two consecutive drops of blood obtained from the fingertip after the participants had been randomly assigned to not wash their hands before testing, expose their hands to fruit, wash their hands following exposure to fruit, or apply different amounts of external pressure to the fingertip being tested.
Control blood glucose measures were taken for comparison purposes following hand washing and drying. Finger prick testing of two blood drops was carried out and then a control value was calculated by averaging the blood glucose measurements obtained from the first and second drops of blood.
When compared with control measures, there was a 10% or greater difference in mean blood glucose levels in 11% and 4% of the first and second drops of blood obtained after blood testing, respectively, following no hand washing. The corresponding differences were 88% and 11% after testing following contact with fruit, and only 4% and 5% after hand washing following contact with fruit.
Exposure to difference external pressures, ie, squeezing versus no squeezing, led to 10% or greater differences in blood glucose from control measures in 5% to 13% of the patients.
The researchers therefore suggest that squeezing the fingertip to obtain blood should be avoided as it may lead to unreliable readings.
"The first drop of blood can be used for self-monitored glucose testing, but only after washing hands," write the authors in the journal Diabetes Care.
They suggest: "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."
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By Helen Albert