Background: Information about how genetic testing is used in the NICU and how it changes clinical management is limited. In addition, genetic testing strategies are rapidly evolving, and having a baseline understanding of our current testing strategies and their clinical utility is important. Among infants admitted to children’s hospitals NICU, about 10-30% have a congenital anomaly or another condition that may necessitate genetic testing. Studies of NICU parents show that most would pursue expanded genetic testing to have diagnostic closure and to guide management decisions. Additionally, genetic information affects how neonatologists think through complex care decisions, and in some situations, may lead to redirection of care.
Methods: Retrospective chart review of patients admitted to the Children’s Hospital NICU between January 1, 2020, and January 1, 2021, and who have received genetic testing or a genetic consultation during admission was conducted. Data collected included demographic variables, clinical variables, and information about genetic testing amongst the eligible patients.
Results: Between January 1, 2020-2021, there were 774 infants admitted to the NICU. Of these, 134 infants (17%) were eligible for the study. Chart review was completed for 55 out of 134 patients (41%). Infant diagnoses included congenital anomalies, respiratory failure, feeding intolerance, and metabolic abnormalities. 73% of patients had a single genetic test sent, 25% had 2 tests sent and 2% had 3 tests sent. Whole exome sequencing was the most sent initial genetic test (55% of patients), followed by gene panel (16%), other (11%), microarray (9%), FISH (4%), karyotype (4%), single gene (2%) of patients. The first genetic test was sent at 3 days of admission (IQR 1-9 days) and test was resulted at 23 days (IQR 18-33 days). A diagnosis was made in 25% of patients. Diagnostic yield was not higher for critically ill patients (27% vs 26%, p=0.939). Redirection of care differed by critically ill vs. not critically ill patients (40% vs. 5%, p=0.001) and not by a genetic diagnosis (7% with diagnosis vs. 17% without diagnosis, p=0.384).
Conclusions: Genetic testing has significant diagnostic yield in the NICU but is often delayed. By widening access using standardized protocols, we may improve time to results, diagnostic yield and impact clinical care. Decisions about redirection of care in the NICU are appropriately made based on clinical severity, but there may be patients in whom an earlier diagnosis provides decisional clarity.