Open Access Research article

Fetal and neonatal samples of a precursor surfactant protein B inversely related to gestational age

Christoph Czernik1*, Gerd Schmalisch1, Christoph Bührer1 and Hans Proquitté2

Author Affiliations

1 Department of Neonatology, Charité University Medical Center, Berlin, Germany

2 Department of Neonatology / Ped. Intensive Care, University Hospital, Jena, Germany

For all author emails, please log on.

BMC Pediatrics 2013, 13:164  doi:10.1186/1471-2431-13-164

Published: 10 October 2013



Alveolar–capillary membrane leaks can increase the amount of surfactant protein B (SP-B) in the bloodstream. The purpose of this study was to measure the concentration of C-proSP-B, a SP-B precursor that includes C-terminal domains, in various body fluids of newborn infants and determine its dependence on gestational age.


C-pro-SPB was measured in amniotic fluid and umbilical cord blood at birth, and in peripheral blood and urine on postnatal day 3 in 137 newborn infants with a median birth weight of 2015 g (range, 550–4475 g) and gestational age of 34 weeks (range, 23–42 weeks).


C-proSP-B levels differed more than 100-fold among samples. The levels (median; interquartile range) were highest in peripheral blood (655.6 ng/mL; 419.0-1467.0 ng/mL) and lowest in urine (3.08 ng/mL; 2.96-3.35 ng/mL). C-proSP-B levels in amniotic fluid (314.9 ng/mL; 192.7–603.6 ng/mL) were approximately half of those in peripheral blood. In cord blood C-proSP-B was slightly lower (589.1 ng/mL; 181.2-1129.0 ng/mL) compared with peripheral blood. C-proSP-B levels significantly increased in all the fluids sampled except urine with decreasing gestational age (p < 0.001).


This novel assay allows for the quantitative measurement of C-proSP-B in blood and amniotic fluid. The dependence of C-proSP-B on gestational age may hamper its use for the detection of alveolar leaks in preterm newborns.

C-proSP-B; Blood; Amniotic fluid; Urine; Immaturity; Preterm infants