A 96-well plate assay for rapidly determining the amount of frataxin in a human sample. Frataxin is immunocaptured within the wells. The quantity of protein is measured by adding a second frataxin specific antibody that is labeled with horseradish peroxidase. This peroxidase changes the substrate from colorless to blue. The rate of color development is proportional to the amount of protein captured in the well and can be monitored at 600 nm. Alternatively the assay can be terminated, at a user defined time, by the addition of 1N HCl (not supplied) and the assay performed as an end point measurement at 450 nm.