FLOW CYTOMETRY IN PRECLINICAL TOXICOLOGY/SAFETY ASSESSMENT - Flow Cytometry in Drug Discovery and Development - page 140

FIGURE 6.5 Statistical comparison of accuracy and precision between manual and flow
cytometric bone marrow methods. Least square mean estimation was performed and 95%
confidence intervals determined for flow cytometric and manual methods in control animals.
Data collected from 15 vehicle control mice including measurements of nucleated erythroid,
myeloid, and lymphoid were used for analysis. Precision and accuracy between flow cytometric
and manual methods were compared. Mean values with associated errors indicate accuracy and
confidence intervals are a representation of precision.

erythroid in the 1000 U/kg dose group. M:E ratio is a commonly used bone marrow
assessment. Repeatedmeasure analysis of variance (ANOVA) modeling ofM:E ratios
actually revealed very good correlation (R

0.99) among methods (Figure 6.7).
Regardless, this discrepancy of absolute values was of some concern.
A definite advantage of flow cytometry over manual cytologic assessment of
bone marrow cells is less ambiguity in determination of cell types as monoclonal
antibodies are employed allowing both positive and negative selection. For

¼

FIGURE 6.6 Comparison of total bone marrow analysis methods in mice dosed with
recombinant human erythropoietin. Right femur was used for smear preparation. Smears were
stained with Advia S60 automated slide staining system and analyzed manually with standard
techniques. Left femur was flushed and prepared for flow cytometry. Note: Denotes significant
difference from control (p 0.05).