Comparison of capillary and venous blood glucose levels using glucometer and laboratory blood glucose level in poisoned patients being in coma

Poisoning is one of the most common medical presentations in a hospital. Hypoglycemic patients are at increased risk of toxicity. The purpose of this study was to compare capillary blood glucose and venous blood glucose measurements using glucometer against laboratory blood glucose in case of poisoned patients being in coma.

During the 6‑month study period, a random sample of 98 patients was admitted in the Department of Poisoning Emergency and Clinical Toxicology of Noor Hospital, Isfahan University of Medical Sciences, Iran from May 2010. Data collected included age, gender, poisoning reason, vital signs, and Glasgow Coma Scale. Capillary blood samples were obtained from the fourth fingertip of the non‑dominant hand. t‑Test, paired t‑test, Pearson’s correlation analysis, and one‑way analysis of variance (ANOVA) were used for analysis.

The mean of capillary blood glucose was 115.7 ± 50.2, of venous blood glucose measured by glucose meter was 117.8 ± 47.3, and of glucose measured in vitro was 115.8 ± 55.1. Mean of blood glucose showed no significant difference with the three mentioned methods. The correlation between capillary and intravenous blood glucose samples measured by glucometer was 0.93, between capillary blood glucose and in vitro measured venous blood glucose was 0.78, and between venous blood glucose measured by glucose meter and in vitro measured sample was 0.81. The mean of capillary and venous blood glucose levels measured by glucose meter, capillary and venous blood glucose levels measured in vitro, and venous blood glucose levels measured by glucose meter had no significant differences.

Using venous blood sample and measuring the glucose level in it by glucometer is an acceptable and advisable method, and capillary blood glucose measurement by using glucometer is not recommended for patients in coma.