Diagnostic performance and heterogeneity of validated flow cytometry scores: a systematic review.

In 30 seconds

This systematic review examined validation evidence for flow cytometry diagnostic scores, focusing on B-lymphoid disorders (B-LPD) and myelodysplastic syndrome (MDS). It included 44 publications: 29 on MDS, covering 10 scores, and 15 on B-LPD, covering 10 scores. Most scores had only one or two validation studies. Across scores with derivation and validation cohorts, sensitivity and specificity differences ranged from -0.25 to +0.29 (validation minus derivation). For the three scores with more than five validation cohorts, sensitivity heterogeneity was consistently high. The authors conclude that reported accuracy varies widely and is difficult to interpret reliably.

Key findings

• The review included 44 publications: 29 on MDS scores and 15 on B-LPD scores.
• Most scores were validated only once or twice.
• Sensitivity and specificity differences between validation and derivation cohorts ranged from -0.25 to +0.29.
• For the three scores with more than five validation cohorts, sensitivity heterogeneity was consistently high.

Why it matters

Diagnostic scores may appear precise, but limited validation and substantial variation across cohorts make published accuracy estimates uncertain. Differences in study design and pre-analytical, analytical, and post-analytical methods may contribute, although the available studies were too few to quantify their effects reliably. This cautions against assuming that reported performance will transfer consistently across settings.

What to keep in mind

The review found few validation studies, often with limited cohorts; the small evidence base prevented reliable quantification of how identified sources of heterogeneity affected performance.