Simplified immunophenotypic analysis by laser scanning cytometry

Immunophenotypic analysis of hematologic specimens is a useful laboratory adjunct to surgical pathology and cytology to confirm or further characterize diagnoses of leukemia or lymphoma. Laser scanning cytometry is a new laboratory technology that has been adapted to perform immunophenotypic analysis of hematologic specimens, with numerous advantages as compared with flow cytometry. In order to make full use of the laser scanning cytometer's capabilities, a new method of specimen preparation and means of performing the immunofluorescent reactions was developed. The technique described in this report, specific only to laser scanning cytometry, enables panels of up to 36 different antibodies to be used on specimens as small as 50,000 total cells. The laboratory methodology is simple, requires 85% less antibody than flow cytometric methods, and allows individual cell cytologic morphology to be correlated with objective physical and fluorescent measurements on a cell-by-cell basis. Other advantages are described in the text. Over the course of nine months in our community hospital, we have used this technique clinically to analyze 172 cases of suspected leukemia or lymphoma. The method has proven remarkably useful, particularly for extremely small specimens such as fine needle aspiration biopsies.