Step 4: Immature populations:

Screening flow cytometry Figure 18

Figure 18: CD34 is a marker that is expressed on immature populations. Please note that the absence of CD34 does not mean that an immature population is not present. Often these immature populations are CD45 dim or CD45 negative. In this example from a bone marrow specimen, CD34 positive events are less than 1% of the total viable cells (see the gating strategy above).

Screening flow cytometry Figure 19

Figure 19: To further analyze the CD34-positive cells you can look at additional markers (CD33, CD19 etc..). In the example above CD34 is on the y-axis while CD19 is on the x-axis, a proportion of the immature cells are B-cell precursors also called stage I hematogones. The CD19-negative and CD34-positive cells are presumably myeloblasts, however, you can check for CD33 expression or other myeloid antigens for confirmation.

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