Comparison of cytochemistry and flow cytometry for leukemia immunophenotyping: a systematic review and meta-analysis

Accurate diagnosis and classification of leukemia are essential for effective treatment planning. Traditional cytochemistry relies on enzyme-based staining for morphological evaluation, while flow cytometry (FCM) employs monoclonal antibodies to detect multiple surface and intracellular markers. This systematic review and meta-analysis compared the diagnostic accuracy of cytochemistry and FCM in leukemia immunophenotyping. A systematic search of PubMed and Google Scholar was conducted according to PRISMA guidelines. Studies evaluating sensitivity, specificity, and accuracy of cytochemistry and FCM in diagnosing acute and chronic leukemia were included. Data extraction covered study characteristics, diagnostic markers, and performance outcomes. Meta-analysis was performed to compare diagnostic values across methods. Eleven eligible studies comprising pediatric and adult leukemia cases were analyzed. Cytochemical stains such as myeloperoxidase (MPO) and sudan black B showed high specificity (91-100%) and moderate-to-high sensitivity (60-97%), while periodic acid–Schiff (PAS) and nonspecific esterase had lower reliability. FCM demonstrated superior diagnostic performance with average sensitivity of 87.7% and specificity of 85.6%, achieving 95% accuracy in several studies. Marker panels including CD3, CD45, CD79a, and MPO enabled precise subtype differentiation and minimal residual disease detection. Cytochemistry remains useful as an affordable screening tool in resource-limited settings, but FCM provides greater sensitivity, specificity, and comprehensive immunophenotypic data, making it the preferred method for leukemia diagnosis and monitoring. Combining both approaches can enhance diagnostic performance across diverse clinical contexts.