Systemic levels of NO₂-CLA metabolites are lower in SCD patients. (A-B) Total NO₂-CLA and DH-NO₂-CLA levels (esterified plus free acid fraction) in healthy (n = 12) and SCD (n = 9) plasma extracts. (C) Representative urine LC-MS/MS chromatograms showing total (top) and isomer-specific NO₂-CLA peaks (middle, bottom). (D) Representative traces for the urine NO₂-CLA beta-oxidation metabolites NO₂-16:2, NO₂-14:2 and NO₂-12:2. (E-F) Quantification of the total NO₂-CLA and its beta-oxidation metabolites in healthy (n = 7) and SCD (n = 6) urine samples. ∗P < .05 by t test (A,B,E) and 2-way analysis of variance (ANOVA) (F) following logarithmic transformation. No statistically significant differences were found between individual urinary NO₂-CLA metabolites in the posttest analysis, but 2-way ANOVA identified SCD as a significant contributor to the total data variance in panel F. DH-NO₂-CLA, dihydro-NO₂-CLA.