Peripheral Blood Monoblast Count
Measures monoblasts, immature white blood cells, in peripheral blood to help evaluate certain leukemias and other blood-forming disorders.
["Monoblasts are not normally expected in peripheral blood, so their presence may suggest an underlying blood-forming disorder."]
Key facts at a glance
- LOINC
- 34923-3
- Short code
- Monoblasts NFr Bld
- Synonyms
- Monoblasts NFr Bld
- Category
- liver
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 10
- Ref high
- 40
- Critical range
- — – 500 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84484
- SNOMED
- 302774002
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test identifies and measures monoblasts, which are immature forms of monocytes, in blood circulating outside the bone marrow. It may be used as part of the evaluation of leukemia or monitoring of a known blood disorder.
Why might I need this test?
A clinician may order this test when abnormal blood counts, symptoms such as fatigue, bruising, fever, or unusual infections suggest a possible blood-forming disorder. It can also help assess the response to treatment for leukemia.
How is the test performed?
A peripheral blood sample is collected, usually from a vein. A laboratory examines the white blood cells, often using flow cytometry or microscopy, to identify and count monoblasts.
How do I prepare for the test?
No special preparation is usually required. Follow any instructions from your healthcare professional, and tell the laboratory if you recently had a bone marrow transplant or received certain chemotherapy or immunotherapy.
Reference range
Adult: 10-40 U/LN/A
No special preparation required. Avoid fatty meals before the test if possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Monoblasts are normally found mainly in the bone marrow and are not usually present in meaningful numbers in peripheral blood. Their presence may indicate bone marrow involvement by acute myeloid leukemia or another myelodysplastic or myeloproliferative condition. Results must be interpreted with the blood count, symptoms, bone marrow findings, and other laboratory tests.
Short name
Monoblast Count
Frequently asked questions
What are monoblasts?
Does a monoblast result diagnose leukemia?
Is this the same as a complete blood count?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
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Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy