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

## TL;DR

A newborn with severe hemolytic disease had incorrect blood test results due to interference from red blood cell fragments, highlighting the need for manual review in such cases.

## Contribution

This case highlights the limitations of automated blood analyzers in neonates with high nucleated red blood cell counts and emphasizes the importance of manual verification.

## Key findings

- Automated WBC counts were falsely elevated due to NRBC interference in a neonate with hemolytic disease.
- Manual correction of blood smear results was essential for accurate diagnosis and treatment.
- Modern hematology analysers may struggle with extreme erythroblastosis in neonates.

## Abstract

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.