13C-oxalate

13C-oxalate (specifically [13C2]oxalate or carbon-13 labeled oxalate) is a stable isotope-labeled form of oxalate used as a diagnostic tracer to measure gastrointestinal oxalate absorption. Administered orally as sodium [13C2]oxalate or [13C2]oxalic acid, it is utilized in the standardized [13C2]oxalate absorption test to differentiate between metabolic (endogenous) and enteric/dietary (exogenous) hyperoxaluria. Because carbon-13 is a non-radioactive, stable isotope, the test is safe for repeated use in both adult and pediatric populations, including patients with calcium oxalate kidney stones, primary or secondary hyperoxaluria, and Crohn's disease. Following oral ingestion, the absorption rate is calculated based on the recovery of labeled oxalate in the urine (typically measured via gas chromatography-mass spectrometry, GC-MS, or LC-MS/MS) or the appearance of 13CO2 in breath samples as an indicator of intraluminal oxalate degradation by the gut microbiome.

Other names

13C-labeled oxalate13C-oxalic acid13C2-oxalate13C2-oxalic acid[13C2]oxalate[13C2]oxalic acidcarbon-13 labeled oxalatecarbon13 labeled oxalatecarbon 13 labeled oxalatecarbon-13 oxalatecarbon13 oxalatecarbon 13 oxalatesodium [13C2]oxalate