BCP-ALL MRD: What the EuroFlow Discordance Review Adds to a Concordance Number

The original standardized BCP-ALL study distinguishes the first comparison from adjudication. Reporting that sequence helps readers understand what an agreement percentage actually describes.

Ask when the agreement was measured

An agreement percentage can describe an initial comparison or a result after additional review. Those are different stages of evidence. When reading a method-comparison paper, find the sequence of decisions before using its final percentage in a presentation or local validation proposal.

The study behind the comparison

Theunissen and colleagues' Blood study, published online in 2016 and in the 2017 issue, developed standardized eight-colour B-cell precursor ALL MRD panels through five multicentre optimization phases. Follow-up evaluation included 377 marrow samples from 178 patients, with comparison against RQ-PCR.

For samples with sufficient acquired cells, the initial concordance was 93%. Discordant results underwent additional investigation, including blind multicentre flow reanalysis and sequencing-based assessment of antigen-receptor targets. After that evaluation the reported concordance increased to 98%. The authors identified both flow interpretation errors and overinterpretation of low-level PCR results. They also noted that applicability during antibody-based therapies still required evaluation. The final agreement is therefore a post-review result in the study setting, not evidence that every initial call was correct.

Original CFCM conceptual review checklist: Preserve first calls; Trace additional evidence; Label the agreement. No patient data, experimental plots or copied source figure. — Original CFCM conceptual diagram. Educational synthesis; not clinical validation.

Preserve both stages in a local comparison

A useful local study proposal can reserve separate fields for the original result, the reason a case was investigated, the additional evidence and the final interpretation. Keep the original calls visible so that another reader can distinguish analytical agreement from agreement achieved after adjudication.

Before beginning, define how discordances will be selected and who will see the other method's result. Then document departures from that plan. This CFCM reporting suggestion does not prescribe a clinical adjudication rule; it asks the team to make its evidence sequence reproducible.

Do not turn a comparison into a universal reference

The practical lesson is to read the comparison design as carefully as the headline number. A local validation must address its own specimens, methods, intended use and uncertainty. If the final interpretation required extra testing, make that dependence explicit rather than presenting the adjudicated percentage as the performance of an unaided first read.

Daily Learning Pill

Put 'initial' and 'after review' beside an agreement number. That small label can prevent a large misunderstanding of what was actually demonstrated.

Use the CFCM clinical cytometry resources to structure a method-comparison reading group. This original ChatGPT/Codex analysis is educational, not independent scientific review or clinical validation.