Elevated concentration of VLCFA in plasma and tissues are the biomarkers for patients with peroxisomal genetic disorders like X-linked adrenoleukodystrophy (X-ALD). However, it is difficult to quantify these VLCFA simultaneous and most of the detection platforms are laborious and time-consuming. Creative Proteomics has established sensitive, reliable, and accurate GC-MS method for quantification of very long-chain fatty acids.