Creatinine reference values in ELBW infants: impact of quantification by Jaffe or enzymatic method.

Objective: Serum creatinine (Scr) reflects to a certain extent glomerular filtration rate in neonates, but postnatal observations also depends on the technique used to quantify Scr (Jaffe colorimetry or enzymatic quantification).

Methods: In an attempt to quantify differences between these techniques, we compared postnatal Scr trends in two consecutive cohorts of extremely low birth-weight (ELBW) neonates before and following a switch from uncompensated Jaffe to enzymatic Scr quantification. Postnatal Scr (Days 1, 2, 3, 4, 5, 6, 7, 8, 9, 14, 21, 28, and 42) in 151 ELBW neonates (uncompensated Jaffe) was compared to 116 more recently admitted ELBW neonates (enzymatic).

Creatinaemia at birth is equal to maternal creatinaemia at delivery: does this paradigm still hold?

Objective: The paradigm that creatinaemia at birth is equal to maternal creatinaemia may also depend upon the quantification technique applied. Paired maternal-neonatal creatinaemia samples in whom Jaffe in both or compensated Jaffe (maternal) and enzymatic quantification (neonate) were applied.

Methods: Extreme low birth weight infants in two time intervals were included when paired maternal-neonatal creatinaemia samples were available.