15-epi-Lipoxin A4 (15-epi-LXA4 ) is an aspirin-triggered eicosanoid believed to be involved in the positive attributes of aspirin therapy for heart, cancer, and human immunodeficiency virus patients. During inflammation, neutrophils are activated. 15-epi-LXA4 , when administered in vivo, inhibits neutrophil activation and dampens inflammation (Takano, 1997). 15-epi-LXA4 is naturally formed in the body via this pathway: Arachidonic Acid (AA)→ 15(R)-HETE→ 15-epi-LXA4 . Aspirin is thought to be involved in the acetylation of prostaglandin G/H synthase, which triggers the conversion of AA to 15(R)-HETE. This assay, which is both sensitive and selective for 15-epi-LXA4 , is essential to researchers studying anti-inflammatory medications.