Urinary ferritin; a potential noninvasive way to screen NICU patients for iron deficiency.

Objective: Building on our previous study, showing a correlation between ferritin in serum and urine, we conducted a feasibility evaluation, measuring urinary ferritin as a potential noninvasive screening test for iron deficiency among NICU patients.

Study Design: This was a prospective analysis of paired serum/urine ferritin levels. We defined iron-limited erythropoiesis by a RET-He <5th percentile lower reference interval (<28 pg).