Blast enumeration in the bone marrow

骨髓细胞计数是骨髓增生异常、骨髓增生综合征肿瘤和急性白血病的诊断、预后和治疗反应评价的关键因素。然而，很少有研究使用标准显微程序检查BM中爆炸计数的准确性和精度。我们通过在含有cd34阳性细胞的BM样本的cd34染色切片中手动计数单个标记和未标记的单核细胞来评估BM活检样本中细胞的真实数量。然后使用该金标准在四位经验丰富的血液病理学家之间测试爆炸计数的再现性和准确性，使用两种方法，吸痰涂片上的差异计数和基于cd34染色BM切片的视觉估计。有很好的观察者间再现性。然而，与金标准相比，涂片和活检中的计数显示出高度的可变性和偏差。此外，涂片计数和活组织检查计数之间的相关性很差。与涂片相比，cd34染色的活检表现出较少的变异性，但阳性偏倚较高，表明在这些制剂中计数被高估。我们的结果表明，如果要根据细胞的显微计数做出重要的诊断、预后或治疗决定，需要比目前使用的更好的计数方法。计数最好是在保存良好的骨髓组织中进行，但应该努力改进如何定义细胞，也许可以使用可应用于组织切片的信息标签组合。计数过程也可以通过使用自动数字成像技术来简化，并且应该认真考虑将结果表示为每个骨髓区域的母细胞而不是骨髓细胞的百分比，因为非母细胞骨髓细胞的数量可能独立于母细胞而变化。

The enumeration of blasts in the bone marrow (BM) is a critical element in the diagnosis, prognosis and therapeutic response evaluation in myelodysplastic and myeloproliferative syndrome neoplasms and acute leukemias. However, few studies have examined the accuracy and precision of blast counting in the BM using standard microscopic procedures. We assessed the true number of blasts in BM biopsy samples by manually counting individual labeled and unlabeled mononuclear cells in CD34-stained sections of BM samples containing CD34-positive blasts. This gold standard was then used to test blast count reproducibility and accuracy among four experienced hematopathologists using both, differential counts on aspirate smears, and visual estimates based on CD34-stained BM sections. There was excellent inter-observer reproducibility. However, the counts in both, smears and biopsies showed high variability and bias when compared to the gold standard. Furthermore, counts on smears and biopsies correlated poorly with each other. Compared to the smears, CD34-stained biopsies showed less variability but a higher positive bias, indicating that counts were overestimated in these preparations. Our results demonstrate that better counting methods than those currently employed are needed if significant diagnostic, prognostic or therapeutic decisions are to be made based on microscopic enumeration of blasts. Counting may be best performed in well preserved marrow tissue within trephine biopsies but efforts should be made to improve how to define blasts, perhaps using a combination of informative labels that could be applied to tissue sections. The counting procedure could also be facilitated by using automated digital imaging technologies, and serious consideration should be given to expressing results as blasts per marrow area rather than as a percentage of marrow cells since non-blast marrow cells may vary in number independently of blasts.