Among these, urine apolipoprotein C‐III was higher in cats with AA amyloidosis (median, 1.38 × 107; range, 1.85 × 105‐5.29 × 107 vs 1.76 × 106; 0.0 × 100‐1.38 × 107; P = .01). This evidence concerns the gene APOC3 and AA amyloidosis.