Agreement Between Urine And Blood Ketones In Pregnant Women With Diabetes

Abstract

LEARNING OUTCOME: To examine the agreement between measurments of urine and blood ketones in pregnant women with diabetes.Urine glucose measuremetns are no longer acceptable because of the confounding of fluid intake, interference by some drugs, a high renal threshold, and the ability to measure capillary glucose reflecting present glucose levels. Urine ketone measurement is subject to similar counfbunders, but is still the clinical standard for ketone measurement Therefore, the agreement between the clinical standard, urine ketone measurement, and a new direct method, capillary blood ketone measurement, was studied in a convenience sample of 18 pregnant women with pre-gestational or gestational diabetes. Urine ketones were measured using both the Kctostix ™ strips and the Acetest™ tablets and blood ketones were measured using the Ketosite™ meter in 100 samples. Capillary blood glucose, urine specific gravity, and time of last void were also measured Measurements from the Ketostix™ strips (urine) and the Ketosite™ meter (capillary) agreed 43% more than expected by chance (Cohens1 K*=0.43, p<0.001,95% CI 0.27–0.58). Acetest™ tablets and Ketosite™ meter agreed 21% more than expected by chance (Cohens‘ K=0.21, p<0.001,95% CI 0.07–0.34). Urine specific gravity was significantly higher in urine samples which were positive for urine ketones using Acetest ™ (p=0.004) and tended to be higher in those positive by Ketostix™ (p–0.065). Capillary beta-hydroxybutyrate was higher in samples corresponding to urine samples which were positive for ketones with both methods (p=0.048). The urine and capillary ketone measures appear to be measuring the same thing, however, the agreement is not so close that the current clinical standard, urine measurement, should go unquestioned. Further research is needed to determine the relationship between urine and capillary ketone levels and to determine which method is a more accurate reflection of ketone status in pregnant women.