Diagnosis of deep vein thrombosis from γ-butylbetaine and L-carnitine in plasma and urine based on untargeted and targeted metabolomics.

Deep vein thrombosis (DVT) is a significant contributor to the global disease burden. This study aimed to identify metabolic biomarkers to compensate for the limitation in specificity and singular nature of D-dimer test. UHPLC-MS was used to examine γ-butylbetaine and L-carnitine levels in clinical and rat blood and urine at different stages of DVT along with analysis of their diagnostic titer and correlation analyses with DVT. γ-Butylbetaine and L-carnitine levels in plasma and urine which trends were similar in plasma and urine of humans and rats with DVT were lower in patients with DVT and rats than those in the control group (P < 0.05); in human plasma, area under the curve (AUC) of γ-butylbetaine and L-carnitine combined with D-dimer was 0.914 (P < 0.001) in the acute group and 0.895 (P < 0.001) in the subacute group, respectively. In human urine, AUC of L-carnitine combined with γ-butylbetaine in the subacute group was 0.855 (P < 0.001). γ-Butylbetaine and L-carnitine can be used to screen and diagnose DVT at different phases. Moreover, γ-butylbetaine and L-carnitine expression levels are similar in humans and rats, providing precise indicators and animal models for in-depth study of the mechanisms underlying DVT development.