Cis-aconitic acid (cis-aconitate) is an organic acid and a recognized intermediate of the tricarboxylic acid (TCA) or Krebs cycle. Biochemically it sits between citrate and isocitrate and is produced and consumed by the enzyme aconitase. The TCA cycle, defined in the early 20th century by researchers such as Hans Krebs, is central to aerobic energy production, and its intermediates are commonly used as metabolic markers. Aconitase, the enzyme that interconverts citrate, cis-aconitate, and isocitrate, contains an iron–sulfur cluster that is sensitive to reactive oxygen species. Because of that sensitivity, shifts in cis-aconitate levels can reflect not only changes in substrate flow through the TCA cycle but also oxidative effects on mitochondrial enzyme function and cellular redox balance.

Elevated urine cis-aconitic acid may be associated with slowed aconitase activity, altered TCA cycle flux, or oxidative stress affecting iron–sulfur enzymes. It can also reflect broader mitochondrial stress or shifts in substrate availability for energy production. Low or undetectable cis-aconitate levels may indicate rapid downstream conversion to isocitrate and normal flux through the TCA cycle, reduced upstream substrate supply, or sampling and timing effects. Interpretation is most informative when reviewed alongside other Krebs cycle intermediates, oxidative stress markers, and clinical context provided by the full Cellular Zoomer panel.

Cis-aconitic acid is included in the Cellular Zoomer to track TCA cycle flux and to highlight potential oxidative sensitivity of aconitase. As part of a multi-marker mitochondrial and redox profile, it helps providers distinguish where energy flow may be slowed or where oxidative effects may be influencing enzyme activity, supporting more precise biochemical interpretation.