Formic acid (HCOOH) is the simplest carboxylic acid and occurs naturally, notably in ant and bee venom. It is normally present at low levels in blood and urine (up to ~ 0.5 mM) but can be present in concentrations as high as 5 mM in acute methanol poisoning. Environmental exposure to formaldehyde can also elevate the blood and urine levels of formate. In the Formate Assay Kit, formate is oxidized to generate a product resulting in color formation (λ = 450 nm) proportional to formate concentration. The kit provides a convenient means for detecting formate in biological samples such as in serum or plasma, cells, culture and fermentation media. There is no need for pretreatment or purification of samples.