Nucleated red blood cells (NRBCs): A valuable asset to a Clinical Laboratory
Eminent Author, Medical Biochemist and Scientist, Technical Education consultant.
AGD Biomedicals (Pvt) LTD. Andheri East, Mumbai.
Under normal physiologic conditions, NRBCs are absent in the peripheral blood of healthy children and adults(1). However, peripheral blood of premature infants and newborns show small numbers of NRBCs, physiologically(2). The presence of NRBCs on peripheral blood smear of children and adults indicate that there is an extremely high demand for the bone marrow to manufacture RBCs and in this process; immature red blood cells in the form of NRBCs are released into the bloodstream(3). NRBC appearance in peripheral blood signifies bone marrow damage and potentially serious underlying diseases such as leukemias (lymphoblastic, myelogeneous, etc), presence of tumors, blood loss, septisemia, myocardial infaction, chronic lung disease, myelodysplasia, aplastic anemia, severe nutritional anemia, myelofibrosis, miliary tuberculosis, and prolonged hypoxia, etc.(3). Increase in NRBCs in the case of critically ill hospitalised patients indicate high mortality and bad prognosis(4). In a clinical laboratory, manual methods (using examination of stained blood smears) can be used for NRBC count. However, concentrations of NRBCs less than 200/µl may be difficult to determine. Hematology analyzer with the facility to determine NRBC offers a practical and accurate method to determine NRBC concentrations of less than 100/µl(5).
CASE STUDY 1
A 54-year-man presented with loss of weight, weakness, increased sweating, and enlargement of superficial lymph nodes. Following were his histogram reports:
COMPLETE HEMOGRAM:
| PARAMETER | VALUE | NORMAL RANGE |
| Hemoglobin | 10.5 g/dl | 13–18 g/dl |
| Total erythrocyte count | 3.8 X 1012/l | 5.0 ± 0.5 X 1012 /l |
| Total leukocyte count | 91.7 X 109/l | 7.0 ± 3.0 X 109/l |
| Differential leukocyte count | ||
| Neutrophils | 08 % | 40–75% |
| Lymphocytes | 92% | 20–45 % |
| Stained peripheral blood smear Microscopic observations | ||
| Hypochromia | ++ | Normal cells |
| Presence of large number of lymphocytes and Nucleated red blood cells detected | ||
| PCV | 30.5% | 36–48% |
| MCV | 88.5 fL | 82–92 fL |
| MCH | 28.5 pg | 27–32 pg |
| MCHC | 33 % | 32–36 % |
| RDW- CV | 15.8 | 12–14 |
| Platelet count | 160 X 109 /l | 150–400 X 109/l |
Histogram Flags
Presence of blast cells and Nucleated Red Blood Cells (NRBCs)
Diagnosis
From the age and history of the patient, very high WBC count, very high lymphocyte count, and presence of NRBC indicate that the patient was suffering from Chronic Lymphocytic Leukemia (CLL).
Bone marrow examination report was recommended.
CASE STUDY 2
A 12-year-boy presented with fever, bleeding gums, weakness, pallor, and loss of weight. His complete hemogram reports were as follows:
COMPLETE HEMOGRAM:
| PARAMETER | VALUE | NORMAL RANGE |
| Hemoglobin | 5.3 g/dl | 12–16 g/dl |
| Total erythrocyte count | 1.67 X 1012/l | 4.0 ± 0.5 X 1012/l |
| Total leukocyte count | 3.4 X 109/l | 7.0 ± 3.0 X 109/l |
| Differential leukocyte count | ||
| Neutrophils | 15 % | 40–75% |
| Lymphocytes | 85% | 20–45 % |
| Stained peripheral blood smear Microscopic observations | ||
| Hypochromia | + | Normal cells |
| Microcytosis | + | Normal cells |
| NRBCs | Occasional | |
| PCV | 13.8% | 36–48% |
| MCV | 86.5 fL | 82–92 fL |
| MCH | 29 pg | 27–32 pg |
| MCHC | 32 % | 32–36 % |
| RDW- CV | 13.1 | 12–14 |
| Platelet count | 17 X 109 /l | 150–400 X 109/l |
Histogram Flags
Nucleated RBCs
Diagnosis
Significant decreases in all types of cells such as RBCs, WBCs and platelets and presence of NRBCs indicate ‘Aplastic anemia’.
Note
Aplastic anemia is a hematological disorder characterized by the presence of severe anemia, leukopenia and thrombocytopenia. Aplastic anemia may be primary or secondary.
Primary reasons: Congenital, epigenetic disorders or autoimmune.
Secondary reasons: Due to effects of prolonged exposure to chemicals (benzene, insecticides, etc.), medicines (chlorpropamide (one of the oral diabetic drug), chloramphenicol (one of the antibiotic used to treat typhoid), isoniazid (one of the drug used to treat TB), etc., physical agents (X-rays, gamma rays), severe infections (viral and bacterial) leading to septicemia, metabolic disorders, etc.
Detailed study of case history was recommended to find out the main cause of aplastic anemia.
Note
(1) Automated hematology analyzers utilise an immature information channel (IMI). This channel uses cell-specific lysing to separate mature cells from immature cells. Once this reaction has occurred, various combined automated techniques such as hydrodynamic focusing, semiconductor diode laser use, fluorescence and light scatter, along with the DC/RF technology determine; if immature cells are present and to flag appropriately for the left shift, immature granulocytes, blasts and NRBCs.
(2) Most analyzers generate suspect flags to help identify abnormal cells. The presence of large number of NRBCs increases the WBC count obtained by automated hematology analyzers. Hence, stained blood smears of such samples should be examined manually using a microscope to confirm total WBC count.
(3) A facility on hematology analyzers gives total nucleated cell count (TNC).
(4) High numbers of NRBCs interfere in the total WBC count. Hence, White blood cell (WBC) counts are corrected manually for nucleated red blood cells (NRBCs); using the following formula:
Corrected WBC = TNC x [100 / (NRBC + 100)]6,7.
Example: If TNC=12,000/µl and NRBC = 16/µl
Corrected WBC= 12,000X 100/16+100)=10,344
Corrected WBC= 10,344/µl
Enhance NRBC Reporting with HT-550 Hematology Analyzer
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AGD HT-550
- The AGD HT-550, a 5-Part Auto Hematology Analyzer, delivers precise measurements of NRBC absolute count and NRBC percentage, offering advanced insights into this important research parameter. Designed for high-performance clinical and research environments, it ensures reliability, accuracy, and efficiency in every sample run.
References
(1) Godkar PB, Godkar DP. Text book of Medical laboratory technology (4th edition, 2024), Bhlani Publishers, Mumbai. India.
(2) Reference ranges for blood concentrations of nucleated red blood cells in neonates. Christensen RD, Henry E, Andres RL, Bennett ST. https://www.karger.com/Article/Abstract/320148. Neonatology. 2011;99:289–294. doi: 10.1159/000320148.
(3) Benie T. Constantino, I(ASCP)SH; MLT,ART(CSMLS), Bessie Cogionis, MLT(CSMLS). Nucleated RBCs—Significance in the Peripheral Blood Film Get access Arrow. Laboratory Medicine, Volume 31, Issue 4, April 2000, Pages 223–229, https://doi.org/10.1309/D70F-HCC1-XX1T-4ETE.
(4) Tayyab Noor, Ayisha Imran, Hassan Raza, Madiha Sarwar, Shereen Umer, Mavra Fatima. Frequency of Nucleated Red Blood Cells in the Peripheral Blood of ICU-Admitted Patients. Editors: Alexander Muacevic, John R Adler. Cureus. 2023 Jan 16;15(1):e33827. doi: 10.7759/cureus.33827
(5) Performance evaluation of the automated nucleated red blood cell count of five commercial hematological analyzers. Da Rin G, Vidali M, Balboni F, et al. https://onlinelibrary.wiley.com/doi/abs/10.1111/ijlh.12722. Int J Lab Hematol. 2017;39:663–670. doi: 10.1111/ijlh.12722.
(6) Clark KS, Hippel TG. Manual, semiautomated, and point of care testing in hematology. In: Keohane EM, Smith LJ, Walenga JM, editors. Rodak’s Hematology: Clinical Principles and Applications, Ed. 5. St. Louis: Elsevier; 2012.
(7) Kathy Doig and Leslie A. Thompson. American Society for Clinical Laboratory Science July 2017, 30 (3) 186-193; DOI: https://doi.org/10.29074/ascls.30.3.186
