Introduction
The development of hematopoietic stem cell transplantation (HSCT) was an extremely important milestone for treating certain malignant and non-malignant hematological diseases. The HSCT process contemplates collecting hematopoietic progenitor cells (HPC) from the donor, conditioning chemotherapy, infusion of HPC, and engraftment.
Mobilized peripheral blood is the most commonly used HPC source for HSCT due to its ease of obtaining through an apheresis procedure and high progenitor cell count yields compared to bone marrow source, which requires a bone marrow aspiration procedure, usually performed in a surgical center under general anesthesia, and requires the collection of higher volumes to reach the amount of HPC desired. The total nucleated cell count (TNC) corresponds to the sum of all nucleated cells in the sample and is used as a reference for the target dose for both sources of HPC.
The TNC provides essential information on the quality of the sample obtained, since an infusion of insufficient number of cells affects the ability to reconstitute the recipient's hematopoietic system. An insufficient TNC can result in poor engraftment, leading to a slow recovery of blood cell production and increasing the risk of complications such as infections and bleeding.
Determination of the number of nucleated cells in bone marrow and peripheral blood samples can be performed automatically by hematological analyzers such as the Beckman Coulter DxH 500 and Sysmex XN-10. This study aims to compare the performance of those equipments in determining hematological parameters in bone marrow and apheresis material.
Materials and methods
We compared the results of 40 HPC samples (20 bone marrow samples and 20 peripheral blood samples collected by apheresis) analyzed in the Sysmex XN-10 and Beckman Coulter DxH 500 equipments. All these specimens were analyzed without dilution and diluted 1:10. The evaluated parameters were: TNC, hematocrit, platelets, lymphocytes, monocytes, and granulocytes.
Results
The analysis of the results showed a positive Pearson correlation coefficient (above 0.9) between XN-10 and DxH 500 equipment for the evaluation of TNC in diluted samples obtained by apheresis (figure 1) and by bone marrow (figure 2).
In pure samples obtained by apheresis the DxH 500 equipment showed non-linearity for TNC but revealed a positive correlation with the XN-10 when evaluating pure bone marrow samples (figure 2). On the other hand, XN-10 equipment showed linearity when correlating TCN between pure and diluted samples obtained by apheresis (figure 1) and bone marrow aspiration (figure 2).
Hematocrit analysis in samples obtained by apheresis showed 90% and 100% of agreement for diluted samples between the equipment and for diluted versus pure samples, respectively, when using the cutoff value of 12%. Hematocrit validation using the Beckman Coulter equipment was impaired due to the sample's viscosity and limited linearity. Also, there was a satisfactory hematocrit correlation for pure bone marrow samples and comparing diluted versus pure bone marrow samples with both equipment.
The results also showed a good correlation when analyzing the platelet count in pure and diluted samples (bone marrow and apheresis) with XN-10 or DxH 500, as well as comparing the diluted samples versus the pure samples.
The use of differential count of nucleated cells (lymphocytes, monocytes and granulocytes) realized by the two evaluated devices was not approved for bone marrow or apheresis samples.
Conclusion
The determination of TNC, platelet and hematocrit counts using the Sysmex XN-10 equipment were satisfactory for both pure and diluted samples obtained by apheresis or bone marrow.
For pure samples obtained by apheresis analyzed by DxH 500, we could observe absence of linearity for TNC and hematocrit. This situation could be explained by the high number of cells in this sample and the consequent high viscosity.
Disclosures
No relevant conflicts of interest to declare.
