Integrating immunophenotyping and morphology in the diagnosis of acute leukemia at the National Oncology Center, Sana'a, Yemen.

Accurate diagnosis of acute leukemia (AL) is essential for management. Morphological assessment is used in resource-limited settings, but interpretation can be challenging in ambiguous cases. Flow cytometric immunophenotyping provides diagnostic precision, yet its utility in Yemen remains underreported. This study aimed to assess the concordance between morphological diagnosis and flow cytometric immunophenotyping in newly diagnosed patients at the National Oncology Center, Sana'a, Yemen, and describe discordant cases and antigen-expression patterns. An exploratory prospective cross-sectional diagnostic-agreement study was conducted in July-August 2024. Seventy-five newly diagnosed patients were evaluated using morphology and immunophenotyping. Concordance, antigen expression patterns, discordant cases, and hematological parameters were assessed. By immunophenotyping, 42 patients (56.0%) had precursor acute lymphoblastic leukemia (ALL), 32 (42.7%) had acute myeloid leukemia (AML), and 1 (1.3%) had Burkitt lymphoma/leukemia. For comparative analyses, the Burkitt case was included in the ALL analytical group. The participants included 40 males (53.3%) and 35 females (46.7%), with ages ranging from 8 months to 75 years (mean 24.5 ± 21.2 years). In the analytical groups, children accounted for 69.8% of ALL-group cases, whereas 81.3% of AML cases were adults. The concordance between morphology and immunophenotyping was 89.3%, with κ = 0.79 (95% CI: 0.65-0.93, p < 0.001). Eight cases (10.7%) were discordant, including reclassification of ALL to AML and vice versa. Aberrant antigen expression contributed to misclassification, with examples of CD19 positivity in AML and CD2/CD7 co-expression in AML profiles. Hematological parameters did not differ significantly between AML and ALL, including platelet count (p = 0.084). Morphology demonstrates high agreement with immunophenotyping in the diagnosis of acute leukemia. Flow cytometry supports more precise lineage assignment, particularly in ambiguous cases and those with aberrant markers. Expanding the diagnostic infrastructure and improving access to immunophenotyping may strengthen leukemia diagnosis and care in Yemen, particularly when used as part of an integrated diagnostic approach.