FAB-MS is a useful technique for the rapid screening of metabolites in the urine and faeces of patients with porphyria.
It provides characteristic porphyrin profiles without the need for lengthy chromatographic separations. Tandem FAB-MS gives additional information on the structure, thus assisting in the identification of new porphyrin metabolites. The porphyrin profiles obtained with FAB-MS are similar to those provided by TLC or HPLC.