Measurement of serum fructose and uric acid levels
Prior to measuring serum fructose concentrations using a fructose
fluorometric assay kit (K611-100; BioVision Inc., Milpitas, CA, USA),
the serum samples were diluted 1:5 in the assay buffer. The assay was
performed in accordance with the manufacturer’s instructions. Glucose
interference was removed using a sample purification reagent. Free
fructose was enzymatically processed, and the metabolites formed were
reacted with the probe to generate fluorescence, which could be measured
at Ex/Em 535/587 nm. The intra- and inter-assay coefficients of
variation (CVs) were 7.8% and 10.2%, respectively.
Serum uric acid levels were determined using an enzymatic assay
performed on an ARCHITECT ci16200 Automatic Biochemical Analyzer (Abbott
Laboratories, IL, USA) using the Architect urid acid Reagent Kit (Abbott
Laboratories), according to the manufacturer’s and supplier’s
instructions. The reference range for serum uric acid levels at the
study center was considered as 155-357 µmol/l, which established 357
µmol/l as a clinical diagnostic cutoff for hyperuricemia in healthy
Chinese participants. The participants’ characteristics are provided in
Table 2.