February 2024
Monthly Digital Case Study
February Slides
NRBC Quick Overview
Quiz
(PDF for print)
| WBC 2.85* (10^3/mm3) | Neutrophils 60.9% |
| RBC 2.37* (10^6/mm3) | Lymphocytes 28.1% |
| HGB 8.2* (g/dL) | Monocytes 9.4% |
| HCT 24.4* (%) | Basophils 1.6% |
| MCV 103 (fL) | Normoblasts, Erythroblasts 58 |
| MCH 34.6 (pg) | Large Platelets 6 |
| MCHC 34.6 (g/dL) | |
| PLT 127 (10^3/mm3) |
Hemodialysis unit.
Leukopenia. Anemia. Anisocytosis (+++). Hypochromic RBCs (+/-). Punctated RBCs/Howell-Jolly bodies (+). Erythroblastosis (acidophilic erythroblasts). Presence of macroplatelets.
Expert's comments:Punctated RBCs/Howell-Jolly bodies (+): Patient with splenectomy. Hypersegmented neutrophils: Patient on hydroxyurea?
Pathology of red blood cells: Abnormal Hb?
Nucleated Red Blood Cell (NRBC) Erythroblasts
Nucleated red blood cells are early precursors of red cells and in normal healthy adults are rarely seen outside of the bone marrow. In a process known as Erythropoiesis various cytokines and growth factors cause progenitor cells such as the Pluripotent hemopoietic stem cells to form committed erythroid progenitor cells – burst forming unit – erythroid (BFU-E). BFU-E gives rise to a more mature progenitor cell the colony forming unit erythrocyte (CFU-E). The CFU-E is extremely responsive to erythropoietin and causes the CFU-S to produce the erythroid precursor known as the Proerythroblast. The proerythroblast is a large cell, with a large round nucleus, finely stippled cytoplasm, deeply basophilic cytoplasm and one or more nucleoli. As the cell matures it decreases in size along with changes to the size of the nucleus and alongside changes to the cytoplasm (see below). After the cell reaches the late (orthochromatic) erythroblast stage, the nucleus is extruded from the cell producing a reticulocyte, the reticulocyte is then released into the blood stream where it matures to a red cell within 24 - 48 hours. It is remarkable to think that every second the human body generates 2 million red cells.
Erythropoiesis
The traditional way of enumerating Nucleated Red Blood cells and therefore providing a Corrected White Cell Count (most automated cell counters produce a Total Nucleated Cell Count (TNC) that may include NRBC as well as WBC) is when performing the differential and the total number of NRBC seen per 100 WBC is counted. The Corrected WBC may then be calculated with the following formula:
Corrected WBC = TNC x [100 / (NRBC +100)]
Automated analyzers like the HORIBA Yumizen series of analyzers are able to enumerate NRBC on every sample with a high degree of accuracy.
In adults the presence of NRBC is rare and if found in numbers has been shown to indicate the presence of numerous diseases e.g. solid tumors, hematological malignancies, hemolysis, hypoxia, nutritional anemia, blood loss, septicemia, myocardial infarct, chronic lung disease, and myelodysplasia. In studies it has been shown that the presence of NRBC in the peripheral blood of adults is a marker for poor prognosis.
NRBC are found in healthy neonates and disappear after approx. one month of life.
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