In the analysis by Anne Cullen (now Anne Cullen Twomey), a first urine specimen with GRP level greater than 20,000 pg/mg creatinine between PND 1–5 occurred among 54% of the infants who later developed BPD (p < 0.001), versus 10% among non-BPD infants (specificity 90%). The gene discussed is GRP; the disease is bronchopulmonary dysplasia.