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

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.