Abstract
Different methods of assessing ketone body concentrations in blood and plasma of ketoacidotic patients have been compared. We confirmed that Ketostix reacts strongly with acetoacetate, giving a useful range of 0 to 10 mM for plasma acetoacetate, that acetone reacts weakly, and that 3-hydroxybutyrate does not react at all. Plasma Ketostix readings correlated only moderately well with enzymatically determined whole-blood acetoacetate. All samples giving a + + + reaction contained more than 1.6 mM acetoacetate while only 4 out of 21 samples showing 0 contained more than 0.4 mM. Comparison of Ketostix readings with total blood ketone body content showed poor correlation. One reason for this was the large variation in the ratio of 3-hydroxybutyrate to acetoacetate in ketoacidosis; another was that often Ketostix had been stored in such a way that they had become damp, which impairs their reliability. If the Ketostix reading and estimation of the blood pH show a discrepancy we suggest that an enzymatic assay should be used to determine the ketone bodies and lactate.