Detecting fetomaternal hemorrhage: a comparison of five methods.

Appropriate postpartum administration of Rh immune globulin relies on sensitive detection and accurate quantitation of fetomaternal hemorrhage (FMH). Recently, the microscopic Du test (micro Du) enhanced with polyethylene glycol (PEG Du) and flow cytometry (FC) have been advocated for this purpose. Three qualitative methods (micro Du, rosette test, and PEG Du) and two quantitative methods (acid elution and FC) for assessing FMH were evaluated with particular attention given to PEG Du and FC. In vitro studies comprised 10 series of dilutions of D+ cord cells in D- adult cells to yield D+ cell concentrations of 0.06, 0.12, 0.25, 0.50, 0.75, 1.0, and 2.0 percent. Additionally, 26 postpartum samples were tested. Of the qualitative techniques, the micro Du test was the least sensitive with 20 percent false-negative results occurring at 0.5 percent fetal cells. The PEG Du test was only slightly more sensitive and offered no clinical advantage. The rosette test was the most sensitive, consistently detecting fetal cells at concentrations of 0.25 percent or greater. FC and acid elution showed similar results, with good correlation obtained between measured and expected quantities of fetal cells (r = 0.99 and 0.96, respectively). One of 26 postpartum samples was positive by all screening techniques; acid elution and FC detected 0.3-percent concentrations of fetal cells and 0.17-percent concentrations of D+ cells, respectively. Although acid elution is a more commonly used method for quantitating FMH, FC offers an acceptable alternative that is capable of analyzing large numbers of cells with objectivity and reproducibility.

Richter's syndrome presenting as primary central nervous system lymphoma. Transformation of an identical clone.

The development of a central nervous system (CNS) large cell lymphoma in a patient simultaneously diagnosed with chronic lymphocytic leukemia (CLL) is reported. Although differences in phenotypic expression were demonstrated in study of the peripheral blood and CNS disease, identical immunoglobulin gene rearrangements were identified, providing evidence for evolution of two morphologically distinct neoplasms from the same clone. Beyond histologic transformation, acquisition of an aneuploid cell population in the CNS tumor was demonstrated by analysis of DNA content. Isolated parenchymal involvement of the CNS by large cell transformation of CLL has not been previously described; its relationship to CNS lymphoma and Richter's syndrome are reviewed.

Glycohemoglobin quantitation by alkaline gel electrophoresis. A reliable technique with practical clinical advantages.

The Beckman Paragon alkaline gel electrophoresis system was evaluated for utility in identification and quantitation of glycosylated hemoglobin in the clinical laboratory setting. In contrast to other alkaline hemoglobin electrophoresis systems, this system provides adequate separation of HbA0 from its glycosylated form. A band anodal to HbA0 was identified as glycohemoglobin; in vitro synthesis of glycohemoglobin confirmed the migration pattern of the glycohemoglobin band. In both in vitro synthesis studies and in a series of 48 patients, quantitation of the glycohemoglobin band by densitometry showed good correlation (r = 0.99 and r = 0.96, respectively) with values obtained by a standard column chromatographic technique. Beyond reliable quantitation of glycohemoglobin, this system offers two advantages. First, it discriminates hemoglobin F and hemoglobins with low isoelectric points that may coincidentally be measured as glycohemoglobin by other techniques. Second, it provides simultaneous detection of common hemoglobinopathies, a necessity for accurate reporting of glycohemoglobin in the diabetic patient with a concomitant hemoglobinopathy.