GC/MS is becoming popular for clinical laboratory medicine, in particular, chemical diagnosis of organic acidemias. In Japan, however, GC/MS is not enough popular still now, probably because of difficulties in maintenance of GC/MS equipments or GC/MS data interpretation, or requirements of knowledge on the inherited metabolic disorders. We developed an automated GC/MS data profiling and disease detection system using a personal computer, and confirmed its usefulness in the following laboratory tests.
1) Standard organic acidemia screening : The solvent extraction of urinary organic acids is a most popular preparation method for organic acidemia screening. About 120 kinds of urinary metabolites that are necessary for the diagnosis were enrolled in advance. We confirmed after the solvent extraction and GC/MS analysis that the data could be automatically processed and profiled urinary metabolites, and that the possible diagnosis was made by this system on a personal computer.
2) Comprehensive neonatal mass screening : In preparation, urinary samples were directly dried up and derivatized. Preparation of the samples enable the analysis of amino acids, carbohydrates or others as well as organic acids. We apllied this system for the screening method and confirmed that this system could automatedly profile GC/MS data of these compounds preset and successfully diagnose the diseases.
3) Stable isotope dilution analysis : The stable isotope dilution method is an extremely sensitive GC/MS analytical method, in particular, for metabolites whose amount is too small. We applied this system to the stable isotope method to determine urinary acylglycines, setting multiple internal standards, and confirmed the usefulness of this system.