Fingerstick glucose determination in shock

Abstract

Objective: To evaluate the accuracy of fingerstick glucose measurements in severely hypotensive patients.

Design: Prospective, nonrandomized comparison study.

Setting: Emergency department in a university hospital.

Patients: Twenty-five severely hypotensive patients (systolic blood pressure less than or equal to 80 mm Hg) and 39 normotensive patients.

Measurements: Simultaneous fingerstick reagent strip glucose, venous reagent strip glucose, and laboratory glucose values were compared. Data were analyzed using error-grid analysis.

Results: In hypotensive patients, the mean fingerstick glucose values were significantly lower than the values obtained either by venous reagent strip or laboratory glucose measurements. Fingerstick glucose values in the hypotensive group were 67.5% of laboratory glucose values, and were significantly lower than the values obtained in the normotensive group (91.8%, P less than 0.001). Only 36% of the hypotensive patients had fingerstick glucose values within the acceptable range of 20% of the laboratory glucose value. Thirty-two percent of hypotensive patients were incorrectly diagnosed as hypoglycemic (glucose less than 3.89 mmol/L [70 mg/dL]); 2 of these patients were actually hyperglycemic (glucose greater than 11.10 mmol/L [200 mg/dL]). Venous reagent strip measurements accurately reflected laboratory glucose values in both hypotensive and normotensive patients.

Conclusions: Fingerstick glucose testing does not accurately represent venous glucose levels in severely hypotensive patients. If fingerstick glucose testing is relied on for these patients, errors in clinical management may be made. Venous reagent strip glucose testing correlates well with laboratory glucose measurements and should be the preferred method for rapid assessment of glucose level in critically ill patients with severe hypotension.