Immunoassays distinguishing between HNL/NGAL released in urine from kidney epithelial cells and neutrophils

► Two ELISAs measure monomeric and dimeric HNL/NGAL in urine. ► The ELISA-2 mainly detected dimeric HNL/NGAL from neutrophils. ► The ELISA-1/ELISA-2 ratio mainly detected monomeric HNL/NGAL from kidney cells. ► The monomer-specific ELISA-1/ELISA-2 ratio increased during AKI development. ► Patients with urinary tract infections had high dimer-specific ELISA-2 levels.