(A) Linear correlations between in the measured redox ratios (NAD+/NADH) as measured using the IR versus conventional lineshape fitting methods, with UDP(G) fitted as four doublets (left panel) and a single pseudo-doublet (right panel). (B) Comparison of the measured NAD+/NADH ratio between different fitting approaches in test and retest separated by two-weeks. (C) Comparison of the relative concentration of various UDP(G) components in test and retest after two-week. The data were from the IR-based fitting analysis with UDP(G) fitted by multi-doublet model. Abbreviations: ATP, adenosine triphosphate; NAD(H), nicotinamide adenine dinucleotide, a combination of NADH and NAD+; UDP(G), a combination of UDP-Gal, UDP-Glc, UDP-GalNAc, and UDP-GlcNAc.