Hematopoietic stem cell transplantation (HSCT) is an established treatment for several malignant and non-malignant hematological disorders. The timing and success of hematopoietic engraftment are important early indicators of transplant recovery.

To describe neutrophil and platelet engraftment kinetics after HSCT and to explore associations of engraftment with patient characteristics, transplant compatibility, graft characteristics, transfusion requirements, and early recorded survival status.

This prospective observational study included 45 consecutive patients undergoing autologous or allogeneic HSCT at a tertiary-care transplant centre in Dehradun, India. Engraftment was defined using predefined neutrophil and platelet count criteria. Patient, transplant, compatibility, graft-quality, transfusion, and early follow-up variables were extracted from the master clinical dataset. Continuous variables were compared using the two-sided Mann–Whitney U test and categorical variables using Fisher's exact test.

Successful hematopoietic engraftment occurred in 40/45 patients (88.9%). Mean neutrophil and platelet engraftment occurred at 13.47 ± 2.99 days and 15.53 ± 4.73 days, respectively. Pre-transplant peripheral-blood CD34+ count was lower in the engraftment group but was not statistically significant (37.15 ± 37.41 vs. 83.59 ± 68.11; P = 0.148). Final infused CD34+ cell dose was also not significantly different (9.15 ± 4.95 vs. 8.60 ± 5.66 × 10 ⁶ /kg; P = 0.732). ABO compatibility was not significantly associated with engraftment (32/35 vs. 8/10; P = 0.306; OR: 2.67, 95% CI: 0.38–18.74). Product viability was lower in the engraftment group (96.34 ± 2.94% vs. 98.69 ± 0.92%; P = 0.045), although this finding should be interpreted cautiously given the small number of non-engraftment events and multiple comparisons. Three deaths occurred, all among patients with non-engraftment.

In this heterogeneous single-centre cohort, most patients achieved hematopoietic engraftment within the first three weeks after HSCT. Neither pre-transplant circulating CD34+ count, final infused CD34+ dose, nor ABO compatibility showed a statistically significant association with engraftment. The small sample size and only five non-engraftment events limit causal inference and multivariable analysis. Larger prospective cohorts with longitudinal donor-chimerism and time-to-event data are required.