Blast Cells, Cerebrospinal Fluid — Manual Count
A microscopic examination of cerebrospinal fluid that counts immature white blood cells, called blasts, which may be present with leukemia.
["This test checks cerebrospinal fluid for blast cells, which can indicate leukemia involvement in the nervous system."]
Key facts at a glance
- LOINC
- 56470-8
- Short code
- Blasts CSF Manual
- Synonyms
- Blasts CSF Manual
- Category
- liver
- Sample
- csf
- Container
- Sterile tube
- 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
- Method
- manual-count
- CPT
- 84484
- SNOMED
- 302774002
- Specimen volume
- 1-2 mL
- Stability
- Immediate analysis required, Refrigerated: 1h
- Hemolysis max
- 200
- TAT
- 4–24 hours
- Order
- routine
What is this test?
This test examines cerebrospinal fluid (CSF), the fluid surrounding the brain and spinal cord, for blast cells. Blasts are immature blood cells that are not normally found in CSF. A manual count means a laboratory specialist reviews the specimen under a microscope.
Why might I need this test?
This test may be used to assess whether a blood cancer such as acute leukemia has spread into the cerebrospinal fluid. It may be ordered when there are neurologic symptoms, when leukemia is diagnosed, or when monitoring the response to treatment.
How is the test performed?
CSF is usually collected through a lumbar puncture, also called a spinal tap. The fluid is sent to the laboratory, where a specialist prepares and examines it under a microscope to identify and count any blast cells.
How do I prepare for the test?
Fasting is generally not required, but you should follow any instructions provided by your healthcare professional. Tell the care team if you take blood thinners, have a bleeding disorder, or have had back surgery, because these factors may affect the procedure.
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.
Finding blast cells in cerebrospinal fluid may indicate involvement of the central nervous system by leukemia or another blood-forming cancer. The result is interpreted with the blood findings, symptoms, imaging, and other laboratory tests. If blasts are detected, the treating team may recommend additional testing and a treatment plan focused on the nervous system.
Short name
CSF Blast Count
Frequently asked questions
Are blast cells normally present in cerebrospinal fluid?
Does this test require a lumbar puncture?
Does the test show how much leukemia a person has?
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.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy