Clinical Significance Of Carboxyhemoglobin In Neonatal ABO Incompatibility

Objective To discuss the clinical significance of carboxyhemoglobin (COHb) in neonatal ABO incompatibility through the analysis of blood examination. Methods A retrospective analysis was conducted of all the131cases of neonatal ABO incompatibility admitted to our hospital from June,2012to January,2013categorized as case group, using121non hemolytic jaundice cases as control. We compared with two groups of gestational age, body weight, morbidity and hospitalization time, COHb, serum total bilirubin (STB), hemoglobin (Hb) and reticulocyte (Ret). Correlation with STB increasing speed (μ mol/L· d) and COHb was analyzed. Area under the receiver operating characteristic (ROC) curve (AUC) and optimum sensitivity and specificity for COHb, Hb and Ret were evaluated. Results The average gestational age of the case group was significantly higher than that of the control group (p<0.01), while no significant differences in body weight (p>0.05). Morbidity and hospitalization time of the case group was earlier than that of the control group (p<0.01). There is no significant differences in STB (p>0.05). RBC, Hb of the case group was significantly lower than that of the control group, while COHb, Ret, STB increasing speed was higher than that of the control group (p<0.01). No significant differences in morbidity and hospitalization time, STB, COHb, RBC, Hb, Ret and STB increasing speed between direct antiglobulin test positive and negative patients of the case group (p>0.05). The linear correlation between STB increasing speed and COHb was positive (r=0.670, p<0.01), which is strong in the direct antiglobulin test positive patients (r=0.851), while weak in the control group (r=0.339). The cut-off value of COHb within10days after birth for optimum prediction of neonatal ABO incompatibility was1.65%, AUC0.734, sensitivity67.9%, specificity68.6%, and the combined detection of Hb and Ret could increase the diagnostic specificity of up to97.3%. The cut-off value of COHb at the second day after birth was1.90%, AUC0.821, sensitivity65%, specificity83.3%, and the combined detection of Hb and Ret could increase the diagnostic specificity of up to99.0%. Conclusion COHb is an early adjunctive marker for detecting neonatal ABO incompatibility, and also an index for estimating the severity of hemolysis. If combined with Hb and Ret detection, the diagnostic efficacy could be greatly improved, which makes COHb an important role in early diagnosis and intervention guiding.