Correlation between blood ketones and exhaled acetone measured with a semiconducting gas sensor

Breath acetone (BrAce) has been reported to be useful for monitoring the pathophysiology of patients with diabetes. However, devices that measure BrAce are expensive, complex and uncommon. The FM-001, originally designed to monitor a marker of weight loss in healthy people, is a device for measuring BrAce. The FM-001 is a loading semiconducting gas sensor that is a simple and reusable device. The aim of this study was to evaluate the correlation between blood total ketone bodies (TKB) and BrAce measured with the FM-001 in patients with diabetes. Furthermore, through evaluation of that correlation, we sought to detect patients at high risk of developing diabetic ketoacidosis (DKA). Thirty-five participants (age 52 [40-57], T2DM 32, T1DM 3) were enrolled. Scatter plots and linear regression lines relating BrAce to TKB and the correlation coefficients were calculated. Receiver-operating characteristic analysis was performed to determine the cut-off for predicting patients prone to DKA. The results showed that BrAce strongly correlates with TKB (R= 0.828), and the correlation was stronger in patients whose serum C-peptide was not low. The optimal BrAce cut-off for predicting risk of developing DKA was 3400 ppb (AUC 0.924, sensitivity 73.3%, specificity 100%), which corresponds to a TKB ⩾ 1000µmol l^-1. BrAce also weakly correlated with free fatty acid. Thus, BrAce levels measured with the FM-001 strongly correlate with TKB, even in patients with diabetes. This suggests the FM-001 is a simple and potentially useful method for detecting diabetic ketosis. (UMIN-ID: UMIN000038086).