Carbon monoxide hemoglobin Test Kit (Colorimetric method)

Isocitric Acid, an isomer of citric acid, is found in large amounts in many fruits and vegetables and in foods made from these ingredients. What organisms can use is type D isocitric acid, a component of the tricarboxylic acid cycle.

The isocitric acid is converted to A-ketoglutaric acid by isocitric dehydrogenase (ICDH, EC1.1.1.41), while NAD (P) is reduced to NAD (P) H, from which the isocitric acid content can be calculated.