LAUSR

BACKGROUND Synthetic colloid solutions, administered by rapid infusion to volume-depleted dogs, might be present in high concentrations in subsequent urine samples. The potential for these solutions to affect the performance of ELISA measurements due to sample matrix effects when studying kidney injury biomarkers requires investigation. OBJECTIVE We aimed to investigate two different synthetic colloid solutions, 4% succinylated bovine gelatin (GEL) and 6% hydroxyethyl starch (HES), for potential interferences with a commercially available canine neutrophil gelatinase-associated lipocalin (NGAL) ELISA. METHODS Assay interference was assessed by measuring the linearity of NGAL concentrations measured using a canine NGAL ELISA after serial dilution of a canine pooled urine sample with an assay diluent, GEL, or HES. RESULTS NGAL recovery from urine specimens containing up to 75% HES and up to 62.5% GEL was within acceptable limits (80%-120%). NGAL recovery from the urine specimen containing 75% GEL was poor (76%). Linear regression analysis demonstrated excellent linearity under dilution when a canine urine sample was diluted with the assay diluent, GEL, or HES. CONCLUSIONS The presence of large amounts (>62.5%) of GEL in canine urine samples could cause negative interference in the performance of the NGAL ELISA investigated.