Formaldehyde may affect the lymphatic and blood systems and that exposure to formaldehyde may cause leukemia, particularly myeloid leukemia, in humans. This Formaldehyde Assay is designed to measure formaldehyde present in urine and tissue culture media samples. Standards or diluted samples are pipetted into a black microtiter plate. The fluorescent reaction is initiated with the Formaldehyde reagent and the emission of the generated fluorescent signal is detected at 510 nm using excitation at 400 nm. The concentration of the formaldehyde in the sample is calculated using software available with most fluorescence plate readers.