Effects of different methods used to take blood samples on blood glucose measurements

This quasi-experimental study with matched samples was aimed at finding out whether venous and capillary blood samples affect blood glucose level measurements and investigating effects of different methods used in skin cleaning before taking a blood sample on the measurement results. The study was carried out in Hafsa Sultan Hospital of Manisa Celal Bayar University between November 27, 2017 and April 30, 2018. The study included 109 patients who presented to the blood collection unit for 75 g OGTT (Oral Glucose Tolerance Test). The study data were collected by the researcher between 8 a.m. and 12 noon. To collect the data, the Personal Information Form, Data Registration Form and a glucose meter were used. In the collection of the data, the procedure used to draw fasting venous blood for the 75 g OGTT was as follows: blood drop glucose measurements were made on the first and second capillary blood samples taken from the middle finger of the right hand cleaned with a 70% alcohol pad without washing the hands, on the first and second capillary blood samples taken from the middle finger of the right hand after washing the hands for 30 sec., on the first and second capillary blood samples taken from the middle finger of the left hand cleaned with a 70% alcohol pad after the hands are washed. Then the measurements were recorded. Then, the patients drank a solution that contained 75 grams of sugar and 2 hours later, blood samples were taken for venous blood glucose measurement. Finally, after the hands were washed for 30 seconds, blood drop glucose measurements of the first and second capillary blood samples taken from the middle finger of the right hand cleaned with a 70% alcohol pad were made. In the analysis of the study data, the Friedman test was used for repeated measures analysis of variance, Bonferroni (Dunn) test was used to perform pairwise comparisons, and Friedman analysis of variance results were summarized as median (min-max). P-values <0.05 were considered statistically significant. In order to carry out the study, the approval of the Manisa Celal Bayar University Faculty of Medicine Health Sciences Ethics Committee, written permission of the Hafsa Sultan Hospital of Manisa Celal Bayar University Faculty of Medicine and informed consent of the individuals included in the study were obtained. The mean age of the patients was 45,56 ± 12,32 years. Of them, 61,5% were female and 46.8% were obese. The fasting capillary blood glucose values obtained by using different aseptic methods were found to be 5% lower than the fasting venous blood glucose value. The first blood drop values of fasting capillary blood glucose were found to be 1-3 mg / dL lower than the second blood drop values. The capillary blood glucose value measured 2 hours after OGTT was approximately 11% higher than the venous blood glucose value. In the study, it was found that the fasting venous blood glucose median before the 75 g glucose load was higher than median values of the capillary first blood drop taken after the hands were washed, or after the fingers were cleaned with the alcohol pad after the hands were washed or after the fingers were cleaned with the alcohol pad (p <0,001). The fasting venous blood glucose median was found to be higher than the median value of the second blood drop (p <0,05) taken after the hands were washed, or after the fingers were cleaned with the alcohol pad after the hands were washed (p <0,05). The difference between the value of the second blood drop taken after the finger was cleaned with the alcohol pad and the venous blood value was not significant p> 0,05). It was found that venous blood glucose value measured 2 hours after OGTT was lower than the values of the first and second capillary blood drops (p <0,05). There was not a statistically significant difference between the first and second capillary blood glucose levels measured 2 hours after OGTT (p> 0,05). It is recommended that when fasting capillary blood glucose is measured, the first blood drop can be used for measurement after hands are washed and fingers are cleaned with alcohol pad, but that the second capillary blood drop should be used if blood glucose levels are high.