Challenges in interpreting leukocyte and nucleated red blood cell counts in neonatal hemolytic disease: A case report on hematology analyser performance.

We present a case of hemolytic disease of the newborn (HDN) due to maternal alloimmunisation with anti-E and anti-c antibodies, resulting in severe anaemia, respiratory insufficiency, and hyperbilirubinemia in a term male neonate. Haematological evaluation using the automated analyser Sysmex XN-3100 (Sysmex Corporation, Kobe, Japan) yielded an erroneously elevated white blood cell (WBC) count of 1 6 3 x 1 0 / L , later manually corrected to 2 8 x 1 0 / L due to extreme nucleated red blood cell (NRBC) interference (> 2,000 NRBCs per 100 WBCs). This case illustrates the analytical limitations of modern haematology analysers in neonates with pronounced erythroblastosis. It emphasises the essential role of manual peripheral blood smear review and interdisciplinary clinical-laboratory correlation in ensuring diagnostic accuracy.