Enumeration of Fetal Red Blood Cells, Hemoglobin‐Specific RBC Cells, and F Reticulocytes in Human Blood

Abstract

Recent advances in analytical cytometry have improved diagnostic tools for the study of erythropoiesis in anemic patients and resolution of differential diagnosis in diseases of the erythron. This article presents three applications of red blood cell (RBC) analysis-quantitation of fetal red cells, F-cell enumeration, and F-reticulocyte analysis-which improve diagnostic precision, sensitivity, and specificity, and provide better laboratory indicators of therapeutic efficacy in a variety of hematologic and obstetric disorders. Such advances also include the measurement and quantitation of RBC hemoglobins and their relative ribonucleic acid levels. These advances not only promise to improve diagnostic accuracy and laboratory precision over techniques such as the traditional manual reticulocyte counting method and the Kleihauer-Betke stain method for evaluating fetomaternal hemorrhage (FMH), but also serve as tools for newer assays of anemia diagnosis and improved clinical outcomes. In addition to the primary methods, supporting techniques for preparing spiked controls, automating data analysis, setting up a fetal hemoglobin acquisition protocol, and assaying reticulocytes using thiazole orange are also presented. C 2019 by John Wiley & Sons, Inc. Keywords: F cells r F reticulocytes r fetal hemoglobin r fetal red cells r fetomaternal hemorrhage r flow cytometry r hemoglobin levels r red blood cells How to cite this article: Davis, B. H. (2019). Enumeration of fetal red blood cells, hemoglobin-specific RBC cells, and F reticulocytes in human blood.

A novel enzyme-linked immunostaining technique based on silk membrane for the prenatal detection of fetomaternal haemorrhage

“…It may lead to fetal anemia, jaundice, edema, and even death ( Carr et al, 2022 ). There are numerous causes of placenta rupture, but the most common are trauma and intrauterine death ( Davis, 2019 ; Hsia et al, 2019 ; Hookins and Vatsayan, 2020 ; Monteiro et al, 2021 ). In the United States, 40% of pregnant women die from trauma, according to statistics ( Krywko et al, 2022 ).…”

Assay for “fetal hemoglobin levels” in erythrocytes: Impact of new In Vitro Diagnostics regulation and expanded applications in sickle cell disease management

“…The second IVD device requirement is to address the actual clinical need in a format that allows both rapid testing to support SCD clinics and additionally address the Obstetrical demand for 24/7 FMH testing availability. Certainly, methods for rapid HbF RBC assays are known 12‐16 and existing CE IVD kits for FMH could easily be modified as done in the current study, additionally modern software algorithms are feasible and advocated to provide for fully automated high precision analysis of flow cytometric files and controls 11 . These features would be requisite specifications for a commercial HbF RBC assay providing requisite rapid turnaround (< 60 minutes time to report), high precision, and moderate complexity ease of use within the laboratory workplace to allow for 24‐hour availability, thus supportive of SCD outpatients clinics, patients in crisis and facilitate a more accurate adjustment of anti‐D therapy in FMH patients.…”

Needed, Assays for “Fetal Hemoglobin levels” in RBCs: Fetomaternal Hemorrhage and Expanded Applications in Sickle Cell Disease Management Could Forge an Evolution in Cellular Diagnostics

“…Whatever the cause for retarded acceptance of the FMH HbF RBC assay into clinical practice, the methodologic technology clearly exists to allow a format would allow rapid cell-by-cell measurements of HbF levels in RBCs to support extended applications in SCD, along with improving the FMH testing needs [17]. The author's assessment, having been among the pioneers of IVD HbF RBC assays [18][19][20][21][22][23][24][25], is that the incremental testing volume of SCD patient in developed countries, cost justified by the savings afforded by reduced hospitalization and morbidity of SCD patients when appropriately dosed by the HbF induction therapies, is sufficient to foster a second-generation IVD cell-by-cell HbF RBC assay. The purpose of this commentary is to provide an experienced perspective as to the optimal design for an IVD HbF RBC assay in an easy to perform, rapid testing format.…”

“…Another variable unappreciated by many labs is the importance of cell fixation and permeabilization steps given the hemoglobin intracellular location. Fixation and permeability conditions (time, concentration, cell counts) are the biggest variables of anti-HbF binding in our experience in developing the current IVD HbF RBC kits of Quik Quant (IQ Products, Groningen, NL) and Fetal Hemoglobin Test (Thermo Fisher Scientific, USA) [Table 1, 24,25]. While understanding an absolute threshold for the physiologic inhibition of RBC sickling is of biologic and physiologic interest, it may be equally relevant simply to measure the proportion of the total cellular hemoglobin that is HbF.…”