Predictive ability of venous blood nucleated red blood cells counts in term infants with perinatal asphyxia: A diagnostic study

Background: Hypoxia induces the release of nucleated red blood cell (NRBC) from marrow storage pool to peripheral circulation of asphyxiated infants. Evaluation of NRBC may have reasonable predictive ability for diagnosing perinatal asphyxia. Methods: A diagnostic study was conducted in a tertiary care hospital enrolling 50 asphyxiated cases and 50 healthy controls. NRBC level/100 white blood cell (WBC) was calculated for all infants within first 6 h of life. Receiver operating characteristic (ROC) curve was constructed to select threshold values. Sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were also calculated. Results: The mean NRBC count/100 WBC for cases was 20.3 ± 8.9 compared to 3.8 ± 1.3 for controls (P < 0.001). NRBC cutoff of >9/100 WBCs has 96% sensitivity, 94% specificity, 94% PPV, and 95% NPV in predicting perinatal asphyxia with area under ROC curve 0.98. Positive likelihood ratio was 16, and negative likelihood ratio was 0.04, with 95% overall diagnostic accuracy. Conclusion: NRBC level could predict perinatal asphyxia with reasonable accuracy.