Home Biomarkers Absolute Nucleated red blood cells

Absolute Nucleated red blood cells

CBC Biomarker

Sample Needed

Collection Type: Blood

Body System

Related System: CBC

Overview

Absolute nucleated red blood cells (NRBCs) are immature erythroid precursors that still contain a nucleus. The test measures the absolute number of NRBCs in peripheral blood (usually reported as cells/µL or cells per 100 white blood cells). In healthy adults NRBCs are normally absent from peripheral blood; their presence suggests accelerated or disordered erythropoiesis or bone marrow disruption. Conditions that may produce NRBCs include severe hemolysis, acute blood loss, hypoxia, sepsis, bone marrow infiltration or fibrosis, and certain hematologic malignancies. Newborns, especially preterm infants, commonly have NRBCs for a short period. Age (neonates vs adults), pregnancy/fetal samples, and recent transfusion or severe physiologic stress change expected values.

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Test Preparation

No special preparation is required

Why Do I Need This Test

Profile: included in a complete blood count (CBC) with differential or as part of an expanded hematology panel.
Symptoms prompting the test: unexplained anemia, rapid drop in hemoglobin, persistent fever/sepsis, signs of hypoxia, bleeding, pallor, or unexplained clinical deterioration.
Conditions monitored/diagnosed: hemolytic anemia, acute hemorrhage, severe infection/sepsis, marrow disorders (leukemia, myelofibrosis), and response to marrow-stimulating therapy.
Reasons for abnormal levels: marrow stress, hypoxia, extramedullary hematopoiesis, marrow infiltration, or laboratory contamination.
Biological meaning: indicates premature release of erythroid precursors from marrow or marrow barrier disruption.
Lifestyle/family: chronic smoking, high-altitude exposure, and inherited hemoglobinopathies (family history) can prompt testing or explain elevations.

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Understanding Test Results

0 cells/µL (normal for adults): no circulating NRBCs; routine.
1–10 cells/µL (mild elevation): suggests recent or mild marrow stress for example, early hemolysis, recovery after acute blood loss, mild hypoxia, or early sepsis.
Correlate with hemoglobin, reticulocyte count and clinical signs.
~10–50 cells/µL (moderate elevation): more significant marrow response or injury; seen in marked hemolysis, severe hypoxia, active hemorrhage, fulminant infection/sepsis, or substantial marrow stress.
Warrants urgent evaluation for underlying cause.
>50 cells/µL (marked elevation) or rapidly rising counts: often indicates severe marrow disruption, extensive extramedullary hematopoiesis, marrow infiltration (leukemia, myelofibrosis), or critical illness; associated with worse prognosis in critically ill adults and requires prompt hematology assessment.
Notes: neonatal reference differs low-to-moderate NRBC counts can be physiologic in the first days of life.
Any detectable NRBCs in an adult peripheral blood sample should prompt clinical correlation; thresholds and reporting units can vary between laboratories.

Normal Range

0 cells/µL (adults)

FAQs

Q: What does a nucleated RBC absolute count mean?

A: A nucleated red blood cell (nRBC) absolute count is the actual number of immature red cells—still containing a nucleus—present per microliter of blood. Normally seen in newborns, detectable nRBCs in older children and adults indicate bone marrow stress or damage (severe hypoxia, hemolysis, infection, marrow infiltration, or hematologic disease). Elevated counts prompt further evaluation with additional tests and clinical correlation.

Q: What causes nucleated red blood cells to be high?

A: High nucleated red blood cells (NRBCs) occur when immature red cells spill into circulation. Common causes include severe anemia or hemolysis, hypoxia, acute hemorrhage, severe infection or sepsis, bone marrow disorders (leukemia, myelofibrosis, marrow infiltration), extramedullary hematopoiesis, and newborn physiology or stress. Toxins, certain drugs, and intense inflammation can also provoke NRBC release.

Q: Is it good to have no nucleated red blood cells?

A: Yes in adults, having no nucleated red blood cells (NRBCs) circulating is normal and generally desirable. NRBCs are produced in bone marrow and normally stay there or appear in fetuses/newborns. Finding NRBCs in adult peripheral blood usually indicates serious stress or pathology (severe hypoxia, sepsis, marrow damage, heavy hemolysis, or recovery after transfusion) and needs medical evaluation.

Q: What does it mean when your red blood cells are nucleated?

A: Nucleated red blood cells (NRBCs) are immature red cells that still contain a nucleus. They normally develop in bone marrow and are expected in newborns, but their presence in adult peripheral blood usually indicates bone marrow stress or injury—severe anemia, hemolysis, hypoxia, infection, marrow infiltration, or after splenectomy. Finding NRBCs warrants prompt medical evaluation to identify and treat the underlying cause.

Q: How to reduce nucleated red blood cells?

A: Reducing nucleated red blood cells requires treating the underlying cause. Correct hypoxia and shock (oxygen, ventilatory support, fluids), control infection or sepsis, and manage severe anemia with transfusion and appropriate iron, B12 or folate replacement. Address bone marrow disorders or malignancy with specialist treatment. Monitor counts and follow up with a hematologist for targeted therapy.

Q: What are the precautions for red blood cell count?

A: Before a red blood cell (RBC) count: fasting is typically unnecessary; avoid strenuous exercise, heavy smoking, and alcohol for 24 hours and stay well hydrated to prevent hemoconcentration. Tell your clinician about recent bleeding, altitude changes, pregnancy, and all medications or supplements (iron, B‑vitamins, diuretics). Follow phlebotomy instructions and relax during the blood draw. Abnormal results may need repeat testing or follow‑up.