New (summer 2018) sick day directives recently linked to by @bkh emphasize the recommendation for measuring ketones from blood:
I was quite interested in this—thanks, @bkh, for posting it! This consensus article by ISPAD (International Society for Pediatric and Adolescent Diabetes) focuses on children and adolescents, but I figure is likely applicable to adults as well: kids are simply a bit more sensitive.
I was particularly interested in this mention:
There are three ketones: acetoacetate, acetone, and beta-hydroxybutyrate. Urine ketone strips measure acetoacetate (AcAc) and acetone (if the strip contains glycine), blood ketone strips measure beta-hydroxybutyrate (BOHB), the predominant ketone in DKA, while most labs measure serum acetoacetate. In acute ketoacidosis, the ketone body ratio (BOHB:AcAc) rises from the usual level of 1:1 to 10:1 or more. In response to insulin therapy, BOHB levels commonly decrease long before AcAc levels do. The frequently employed nitroprusside test only detects AcAc in blood and urine and so routine urine ketone monitoring often shows prolonged ketonuria even when significant ketoacidosis and hyperketonemia have already responded to treatment. The prolonged ketonuria can result in confusion when there is clinical improvement following successful sick day management. In fact, if the persistent ketonuria leads to additional insulin administration when it is no longer needed, either at home or in emergency rooms/hospital settings due to a desire to “clear” the urine ketones, hypoglycemia can ensure. Monitoring blood ketones prevents this problem as BOHB declines directly in response to insulin therapy. In fact, declines in BOHB levels will be clinically evident even before declines in blood glucose levels.
I always knew that blood ketone meters were “better” but I assumed it only meant they were more precise. This article implies that the difference between blood and urine ketone measurements can have significant consequences on sick day treatment, which is, of course, one of the more worrisome moments for PWDs.
I will read more on the subject, but this article is compelling to me.