Diagnostic Accuracy of Point-of-Care Testing for Diabetic Ketoacidosis at Emergency-Department Triage

β-hydroxybutyrate versus the urine dipstick

  1. Michael Menchine, MD, MPH1
  1. 1Department of Clinical Emergency Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
  2. 2Keck School of Medicine, University of Southern California, Los Angeles, California
  1. Corresponding author: Sanjay Arora, sanjay.arora{at}usc.edu.

Abstract

OBJECTIVE In the emergency department, hyperglycemic patients are screened for diabetic ketoacidosis (DKA) via a urine dipstick. In this prospective study, we compared the test characteristics of point-of-care β-hydroxybutyrate (β-OHB) analysis with the urine dipstick.

RESEARCH DESIGN AND METHODS Emergency-department patients with blood glucose ≥250 mg/dL had urine dipstick, chemistry panel, venous blood gas, and capillary β-OHB measurements. DKA was diagnosed according to American Diabetes Association criteria.

RESULTS Of 516 hyperglycemic subjects, 54 had DKA. The urine dipstick had a sensitivity of 98.1% (95% CI 90.1–100), a specificity of 35.1% (30.7–39.6), a positive predictive value of 15% (11.5–19.2), and a negative predictive value of 99.4% (96.6–100) for DKA. Using the manufacturer-suggested cutoff of >1.5 mmol/L, β-OHB had a sensitivity of 98.1% (90.1–100), a specificity of 78.6% (74.5–82.2), a positive predictive value of 34.9% (27.3–43), and a negative predictive value of 99.7% (98.5–100) for DKA.

CONCLUSIONS Point-of-care β-OHB and the urine dipstick are equally sensitive for detecting DKA (98.1%). However, β-OHB is more specific (78.6 vs. 35.1%), offering the potential to significantly reduce unnecessary DKA work-ups among hyperglycemic patients in the emergency department.

  • Received October 4, 2010.
  • Accepted January 7, 2011.

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  1. Diabetes Care
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