The earliest time for haematocrit check after packed red blood cell transfusion among children with anaemia

Background . Haematocrit check after red blood cell transfusion remains relevant in paediatric healthcare. The common practice of checking haematocrit at least 24 hours after transfusion has been challenged by recent evidence supporting much earlier timing. Available data are, however, limited and inconclusive.  Objective . To document the changes in haematocrit levels and to determine the earliest time of haematocrit stabilisation after packed red blood cell transfusion in children aged 29 days to 15 years.  Methods . This was a prospective observational study among 114 eligible participants. Capillary haematocrit was obtained pre-transfusion and at 1, 6, 12, 24 and 48 hours after transfusion. Post-transfusion haematocrit was considered to have stabilised if the difference in mean serial levels within at least 3 consecutive timed intervals was ≤1.8%. Target outcome was the earliest time to haematocrit stabilisation. Mean haematocrit at the earliest stabilisation time was compared with the expected level using the Student t -test.  Results . The age range of the 103 subjects analysed was 1.5 months - 14 years with a median of 48 months (interquartile range 12 - 96 months). Haematocrit increased significantly from pre-transfusion to 1-hour post-transfusion level and declined subsequently. The maximum difference between measurements at 1, 6 and 12 hours was 0.7%. In disaggregated analysis, it was 0.7%, 0.4%, 0.7% and 1.1% among subjects <1 year, 1 - <5 years, 5 - <10 years and 10 - 14 years old, respectively. The mean observed haematocrit at the first hour was similar to the expected level.  Conclusion . Post-transfusion haematocrit stabilised at the first hour. Haematocrit checking as early as 1 hour after packed cell transfusion is recommended in children.