Rapid immunotyping of B-cell non-Hodgkin's lymphomas by flow cytometry. A comparison with the standard frozen-section method

The authors compared immunotyping (IT) results obtained by both standard frozen section (FS) and flow cytometry (FC) methods on 218 biopsies suggestive of lymphoma to learn the advantages of each method. The independent interpretations of the FS and FC IT results were concordant in 93% (202 of 218) of cases. The 16 cases with discordance were reviewed and seven causes for discrepancy found: methodologic problems, focal lymphomatous involvement, more sensitive light chain detection by FC, inadequate sample for FC, interpretation error, sample mislabeling for FC, and unexplained. Eleven of the concordant B-cell non-Hodgkin's lymphomas (NHLs) studied by FC did not have a κ:λ ratio of 3 or greater or 0.5 or less and were shown to express light chain restriction by a D-value of 15 or greater with the use of statistical analysis of the κ and λ histograms or by multiparameter analysis of large versus small cells. The authors found both methods to be effective for phenotyping lymphomas, however, each has distinct features, making them complementary in their applications.