Assessment of leukocyte alkaline phosphatase by image analysis.

We have shown that it is possible to automate the assessment of leukocyte alkaline phosphatase by using an azo dye cytochemical staining procedure and a commercial, highly sophisticated image analysis instrument originally designed specifically as a differential white cell counter. The data to date indicate that values obtained by this approach are at least as precise and accurate as current manual techniques. Instrumental analysis avoids the subjectivity associated with manual interpretation of staining intensity and should permit meaningful interlaboratory comparisons. The stability of the stained smears upon exposure to immersion oil or Polymount mounting medium proved to be an unexpected bonus. In addition to such functional data on leukocytes as illustrated by this report, these instruments, with appropriate staining methods and software, can also provide clinically useful quantitative data on red cells, as have been described for reticulocytes. We hope to see more clinical applications in the future for these expensive and target-oriented image analysis instruments. They are capable of automatically providing objective quantitative information on a cell by cell basis--providing feature data that cannot be obtained by other means.