Capillary blood beta-hydroxybutyrate measurement by reagent strip in diagnosing diabetic ketoacidosis.

Abstract

OBJECTIVE: To compare blood beta-hydroxybutyrate (beta-OHB) levels measured by reagent strip with serum ketone levels assessed by the nitroprusside reaction in diagnosing diabetic ketoacidosis (DKA). DESIGN: Prospective study of DKA in 19 Thai diabetic patients from September 2001 until August 2002. SETTING: A university hospital. PATIENTS: Nineteen patients with DKA and ten patients with metabolic acidosis from other causes. INTERVENTIONS: Capillary blood alpha-OHB was measured by a blood ketone meter (MediSense Optium). Concurrently, serum ketone was measured semiquantitatively by nitroprusside reaction (Ketostix, N-multistix, and Labstix). MAIN OUTCOME MEASURE: Sensitivity, specificity, and ROC curve of both methods in diagnosing DKA. RESULT: Mean age +/- SD of DKA patients was 45.6 +/- 16.95 years. Plasma glucose was 675.25 +/- 188.15 mg/dL, arterial blood pH 7.19 +/- 0.12, anion gap and serum bicarbonate 29.93 +/- 4.90 and 8 +/- 3.35 mmol/L. Serum ketone was moderately to markedly positive in most cases. Capillary beta-OHB ranged from 2.4 to >6 mmol/L. The sensitivity and specificity of serum ketone by nitroprusside reaction in diagnosing DKA were 95% and 100%. The sensitivity and specificity of capillary beta-OHB was 90% and 100% respectively. The areas under ROC curves of serum ketone and capillary beta-OHB were 0.975 and 0.950 (NS) respectively. CONCLUSION: Serum ketone and blood beta-OHB measurement are equally effective in diagnosing DKA among uncomplicated cases.