Introduction Increased intestinal permeability may precede the onset of several important diseases in preterm infants including necrotising enterocolitis (NEC) and Gram negative septicaemias.

Hypothesis that increased intestinal permeability is evident at 2 weeks of age and may precede the onset of NEC or Gram negative septicaemias.

Methods Infants <31 weeks gestation were enrolled. Intestinal permeability was assessed by the sugar absorption test (SAT) using lactulose and mannitol and gut leakage by stool alpha-1-antitrypsin (A1AT). Clinical data were prospectively collected.

Results Thirty-six infants were enrolled. The median (range) gestation was 27 weeks (24–30) and median birth weight was 900g (585–1460). Nine infants (25%) developed suspected or proven NEC (any NEC) of whom 5 (14%) developed ≥Bells Stage II NEC. Four infants (11%) developed Gram negative septicaemias. Results are compared between infants with either NEC or sepsis and those with neither.

The median (range) lactulose:mannitol ratio (L:M) for all infants was 0.38 (0.01–5.46) and median A1AT was 128 (41–1518) mg/L. There was no statistically significant difference by L:M in infants who developed any NEC (p = 0.75); ≥Bells Stage II NEC (p = 0.82) or sepsis (p = 0.21) nor of stool alpha-1-antitrypsin in those with any NEC (p = 0.70); ≥Bells Stage II NEC (p = 0.87) or sepsis (p = 0.81).

Discussion In this cohort, the SAT by lactulose:mannitol ratios and stool A1AT did not show evidence of increased intestinal permeability at 2 weeks of age in infants who subsequently developed NEC or sepsis.