Using red blood cell indices for hemoglobin H disease screening in neonates with early neonatal jaundice

Abstract

Objective: The diagnostic research aimed to determine the predictive values of red blood cell indices for screening HbH in neonates with early neonatal jaundice. The red blood cell indices consisted of MCV, MCH, and MCHC.

Materials and Methods: The purposive samples were neonates with early neonatal jaundice receiving phototherapy at Queen Savang Vadhana Memorial Hospital from October 2019 to October 2020. These neonates were divided into four groups according to their hemoglobin typing as followed; 1) neonates with normal hemoglobin typing for age, 2) neonates with HbH disease (Hb Barts>25% or presence of HbH at birth), 3) neonates with Hb Barts between 1-25%, and 4) neonates with other abnormal hemoglobin typing e.g.Hemoglobin E. Descriptive statistics were frequency, percentages, mean and standard deviation. Chi-square test and one-way analysis of variance were used to compare the percentages and mean among the four groups. Unpaired t-test was used to compare mean and standard deviation between two independent groups. Univariate analysis was used to analyze risk ratio with 95% confidence interval (95%CI) in various values of red blood cell indices for predicting HbH. Sensitivity, specificity, accuracy, positive and negative predictive values were calculated at various values of red blood cell indices to predict HbH diseases. The statistical significance was considered as P value less than 0.05.

Results: Five hundred and four neonates were enrolled, of whom six were affected by HbH disease. The incidence rate of HbH disease was 11.9 per 1000 live births. The demographic and clinical characteristics including sex, body weight, gestational age, age at admission and route of delivery among the four groups were not different. As compared to the other groups, the HbH group had the lowest significance for MCV, MCH, and MCHC (p<0.05). The strongest cut-off points of red blood cell indices that suggest the risk for HbH disease were MCH<27 pg combined with MCHC<32 mg/dL. The risk ratio was 355.0 (95% CI=47.4-2658.1) when compared with MCH>27 pg and MCHC>32 mg/dL. Additionally, the MCH<27 pg combined with MCHC<32 mg/dL had sensitivity and specificity at 0.71 and 1.00, respectively. Its accuracy, positive and negative predictive values were 0.99, 0.71, and 1.00, respectively.

Conclusion: This study suggested that hemoglobin typing should be performed in neonates with early neonatal jaundice who had MCH<27 pg and MCHC<32 mg/dL.