Bone marrow hematogones (B-lymphocyte precursors) may cause problems in diagnosis because of their morphologic and immunophenotypic similarities to neoplastic lymphoblasts. The purposes of this prospective, multiparametric flow cytometry study were to quantify hematogones across age groups and a spectrum of clinical conditions, to identify factors that affect the relative quantity of hematogones, and to compare their immunophenotype with that of neoplastic lymphoblasts. A total of 662 consecutive marrow specimens were analyzed for hematogones using one of two 4-color antibody combinations; hematogones were identified in 528 (79.8%). There was a significant decline in hematogones with increasing age (P < .001), but a broad range was found at all ages and many adults had a relatively high number. Specimens processed by density gradient had a higher mean percent hematogones than those processed by erythrocyte lysis (P < .001). There was a direct decline in hematogones with increasing marrow involvement with neoplastic cells. A total of 8% of the 662 specimens contained 5% or more hematogones: 24.6% of specimens from patients aged less than 16 years and 6.3% from those 16 and older (P < .000 01).

Morphologic distinction of leukemic lymphoblasts in B acute lymphoblastic leukemia (B-ALL) from their nonneoplastic counterparts in bone marrow (hematogones) can be difficult. Thus, the presence of aberrant antigen expression detectable by flow cytometry may be critical for diagnosis of B-ALL and detection of minimal residual disease. The current study examined the immunophenotype of B-lineage leukemic lymphoblasts in 200 consecutive, unique, pretreatment patient specimens. We found that all cases of B-ALL exhibited multiple immunophenotypic aberrancies by which they can be distinguished from hematogones. The most frequent aberrancies were uniform or a spectrum of expression of terminal deoxynucleotidyl transferase and CD34, underexpression of CD45, overexpression of CD10, underexpression of CD38, and underexpression of CD20. Asynchronous coexpression of CD34 and CD20 was also frequently observed. Of the 200 cases, 86.5% expressed myeloid-associated antigens, and 19.0% expressed 3 or more. Of 200 cases, 9.0% aberrantly expressed T cell-associated antigens. There were significant differences in antigen-expression patterns between adult and pediatric B-ALL. Specific aberrancies correlate with recurrent cytogenetic abnormalities in B-ALL.

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We describe a simple method for displaying and evaluating the concordance or discordance between cytotechnologists (CTs) and cytopathologists (CPs) on gynecologic cases. The provisional diagnoses made by the CTs and the final diagnoses of the CPs are captured by the laboratory information system; data generated for specified periods are displayed as a 10 x 10 matrix that classifies each possible diagnosis made by the CT and CP into 1 of 10 major categories. Matrices are generated for the entire laboratory and for individual CTs; individual CTs are evaluated based on their deviation from the laboratory average. Three statistical measures are generated: percentage of discordant diagnoses, a kappa statistic, and a weighted measure. During a 2.5-year period, approximately 4,200 cases were referred to a CP for review every 6 months. The median discordance in diagnoses increased during 2 years from 21% to 34%, and the kappa value fell from 0.69 to 0.38. This was attributed primarily to 1 CT, whose performance, as well as that of the entire laboratory, improved after remedial action. Measures of CT-CP diagnostic concordance are a useful and efficient measure of CT performance and can be incorporated into mandatory semiannual performance evaluations.

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