Background: Trimethylaminuia is an unusual observation, often termed fish odor syndrome. The condition results from reduced ability to oxidize trimethylamine (TMA), which has a fishy odor, into odorless trimethylamine N-oxide (TMAO).
Method: Proton nuclear magnetic resonance spectroscopy (MRS) was used as a simple and rapid method to detect TMA and TMAO in the same urine sample without pretreatment. Subjects were considered to have deficient N-oxidation of TMA if the TMAO/TMA ratio was greater than 80 p. 100 (heterozygous) or 65 p. 100 (homozygous).
Discussion: Direct proton RRS analysis of urine is well suited for diagnosis of fish odor syndrome. It can be used to detect heterozygous patients and also provides an easily implemented follow-up tool.