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Introduction: Mutational complexity or tumor mutational burden (TMB) influences the course of chronic lymphocytic leukemia (CLL). However, this information is not routinely used because TMB is usually obtained from whole genome or exome, or from large gene panel high‐throughput sequencing. Methods: Here, we used the C‐Harrel concordance index to determine the minimum panel of genes for which mutations predict treatment‐free survival (TFS) as well as large resequencing panels. Results: An eight gene estimator was defined encompassing ATM, SF3B1, NOTCH1, BIRC3, XPO1, MYD88, TNFAIP3, and TP53. TMB estimated from either a large panel of genes or the eight gene estimator was increased in treated patients or in those with a short TFS ( 6 months). Strikingly, the eight gene estimator was also highly informative for patients with Binet stage A CLL or with a good prognosis karyotype. Conclusion: These results suggest that the eight gene estimator, that is easily achievable by high‐throughput resequencing, brings robust and valuable information that predicts evolution of untreated patients at diagnosis better than any other parameter.

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Key Clinical Message Differentiating chronic myelogenous leukemia in primary blast crisis (CML‐BC) from de novo BCR‐ABL1‐positive acute myeloid leukemia (AML) is a diagnostic challenge with therapeutic consequences. In our case, a basophilia, the presence of the Philadelphia chromosome in all metaphases and the strict exclusion of molecular hallmarks of AML lead us to retain the diagnosis of CML‐BC rather than BCR‐ABL1+ AML.

Background: The Kleihauer–Betke test (KBT) is the most widely used assay for fetomaternal hemorrhage (FMH) detection in rhesus D negative women. In the current study, we sought to evaluate the performance of a flow cytometry (FCM) kit (FMH QuikQuant) using an anti-HbF antibody. Methods: Eighty-three pregnant women, 58 umbilical cord blood (UCB) dilutions in adult blood, and 6 control samples were tested in parallel with FCM and KBT. Results: Firstly, we compared for each assay, on the 58 UCB preparations, results obtained to dilutions prepared. FCM results showed an excellent correlation (r = 0.97), a high reproducibility with a coefficient of variation lower than 20% for values reaching 10 fetal RBCs. KBT values were correlated (r = 0.94) but exhibited a poor reproducibility. Then, we compared both techniques on all samples. FCM showed a good correlation with KBT (r = 0.87) but the KBT exhibited a systematic overestimation of the FMH. For 8 out of 83 pregnant women, KBT was positive. Five were concordant with FCM results (KBT+/FCM+). On the three discordant (KBT+/FCM−), 2 were finally classified as false positive of the KBT because a second control sample was negative and additionally, FCM identified an increased rate of F cells. One discordant case (KBT+/FCM−) remained unexplained. By receiver operating characteristic analysis, we found a threshold at 4.5 RBCs for FCM with a sensitivity of 89.8% and a specificity of 93.2%. Conclusions: The FMH QuikQuant kit is a reliable and highly reproductive FCM method for FMH quantification. © 2012 International Clinical Cytometry Society