Urinary acetoacetate or capillary beta-hydroxybutyrate for the diagnosis of ketoacidosis in the Emergency Department setting

Eur J Emerg Med. 2004 Oct;11(5):251-8. doi: 10.1097/00063110-200410000-00003.

Abstract

Objectives: We compared the semiquantitative measurement of acetoacetate using urinary dipsticks with the bedside quantitative fingerprick measurement of the principal ketone bodies 3-beta-hydroxybutyrate, for the diagnosis of ketoacidosis.

Methods: This is a one year retrospective study of patients who presented with hyperglycemia levels of 250 mg/l or greater in the Emergency Department setting. We compared the sensitivity, specificity, and predictive value of ketonuria and ketonemia for the diagnosis of ketoacidosis (urine or blood ketone bodies, blood bicarbonates <20 mmol/l, anion gap >16 meq/l) in a sample of patients for whom the levels of ketone bodies in the blood and urine as well as serum electrolytes were available.

Results: We studied 355 hyperglycemic patients. The median time between arrival and dipstick testing was 21 min, and was greater than 2 h in more than 10% of cases. Comparison between ketonuria and ketonemia was performed in 173 patients (6% with diabetic ketoacidosis). Ketonuria equal to or less than one cross or a 3-beta-hydroxybutyrate value lower than 3 mmol/l enabled ketoacidosis to be excluded (negative predictive value 100%). At two-cross cutoff points for ketonuria and at the 3 mmol/l cutoff point for ketonemia, the two tests had the same sensitivity (100%), but the specificity of 3-beta-hydroxybutyrate (94%) was significantly higher (P<0.0001) than that of ketonuria (77%). The best positive predictive value for ketonemia was obtained at the 5 mmol/l cutoff point (100%) and for ketonuria at the three-cross cutoff point (26%). At the three-cross cutoff point for ketonuria and at the 5 mmol/l cutoff point for ketonemia, the two tests had the same negative likelihood ratio (0.1), but the positive likelihood ratio of 3-beta-hydroxybutyrate (infinite) was higher than that of ketonuria.

Conclusion: The measurement of 3-beta-hydroxybutyrate in capillary blood is faster and more effective than the use of dipsticks in the urine to detect ketoacidosis in the Emergency Department setting.

Publication types

  • Comparative Study

MeSH terms

  • 3-Hydroxybutyric Acid / analysis
  • 3-Hydroxybutyric Acid / urine*
  • Acetoacetates / analysis
  • Acetoacetates / urine*
  • Biomarkers / analysis
  • Capillaries / chemistry
  • Critical Illness
  • Diabetic Ketoacidosis / diagnosis
  • Diabetic Ketoacidosis / urine*
  • Emergency Service, Hospital*
  • Emergency Treatment / methods
  • Female
  • Humans
  • Ketone Bodies / urine
  • Male
  • Predictive Value of Tests
  • Prognosis
  • Retrospective Studies
  • Risk Assessment
  • Sensitivity and Specificity
  • Urinalysis / methods*

Substances

  • Acetoacetates
  • Biomarkers
  • Ketone Bodies
  • acetoacetic acid
  • 3-Hydroxybutyric Acid