An improved method for quantification of very long chain fatty acids in plasma

Most peroxisomal disorders can be detected via analysis of very long chain fatty acids (VLCFA) and phytanic acid in plasma or serum. Previous methods utilizing gas-liquid chromatography (GLC) alone are time consuming and are hampered by interference from cholesterol derivatives. We describe here a GLC-mass spectrometry method for the simultaneous quantification of VLCFAs and phytanic acid. The method employs single ion monitoring with deuterated internal standards. We studied 38 normal controls and 12 patients with peroxisomal diseases and found complete discrimination between the two groups. Comparison with other methodology is discussed. We believe this to be a practical and accurate method for the quantification of both VLCFAs and phytanic acid in serum or plasma. It should be useful for laboratories involved in the diagnosis of biochemical disorders.