Neonatal Screening: Mean haemoglobin and red cell indices in cord blood from Omani neonates

The aim of this study was to validate the interpretation of red blood cell indices in complete blood count (CBC) and high performance liquid chromatography (HPLC) results on cord blood samples in consecutive Omani neonates.

Cord blood samples from 7,837 neonates, were analysed with CBC and HPLC using the β-thalassaemia short programme. Direct sequencing of abnormal samples with HbS, HbD, HbE and HbC was performed to validate the HPLC results. Additionally, in cases with HbA β10%, the β-globin gene was directly sequenced for β-thalassaemia mutation analysis.

Overall, 4,042 subjects (51.58%) had normal HPLC (HbA 22.88±8.03; HbF 77.02±8.04), whereas the presence of Hb Barts in the remaining 3,795 cases (48.42%) indicated the presence of α-thalassaemia. No case of HbH was detected. In the former subgroup respectively, the mean Hb (15.38±2.04 g/dl) red blood cell (RBC) count (4.69±0.68 × 10(12)/l), Hct (50.5±7.18%), mean corpuscular volume (MCV) (107.66±7.75 fl), mean corpuscular haemoglobin (MCH) (33.31±4.07 pg), mean corpuscular haemoglobin concentration (MCHC) (30.98±3.44 g/dl), red cell distribution width (RDW) (17.01±2.17%) whereas, in the latter group with α-thalassaemia, it was (14.79±2.90 g/dl); (5.09±0.77 × 10(12)/l); (49.7±7.40%); (97.29±13.8 fl); (29.74±11.80 pg); (30.39±3.6 g/dl), and (18.09±2.56%) respectively. DNA sequencing of samples with abnormal haemoglobin could validate the CBC and HLPC interpretations in all cases.

This is the first study comparing the hemoglobin and red cell indices in the cord blood from newborn Omani subjects with those from other countries in the region, showing comparable results to those seen in Saudi neonates. The study also validates the CBC and HPLC interpretations of the cord blood red cell indices in the Omani neonate. The incidence of α-thalassaemia diagnosed by the presence of Hb Barts in cord blood of neonates was 48.42%.