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Blast Cells, Fluid — Number Fraction

Published: August 9, 2026Updated: August 17, 2026

Measures the proportion of blast cells in a fluid specimen to help identify abnormal immature white blood cells.

Quick summary

["An increased blast-cell proportion in fluid may indicate an abnormal blood-forming or immune-cell process."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
26448-1
Short code
Blasts NFr Fld
Synonyms
Blasts NFr Fld
Category
liver
Sample
serum
Container
Red-top tube (SST)
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
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What is this test?

This test measures the proportion of blast cells in a fluid specimen. Blast cells are immature precursor cells that normally develop into blood or immune cells.

Why might I need this test?

A clinician may order this test when fluid is collected because of unexplained symptoms or when a blood disorder is suspected. It can help determine whether abnormal immature cells are present outside the bloodstream.

How is the test performed?

A laboratory examines the fluid, identifies and counts the cells present, and calculates the percentage that are blasts. The examination method may vary with the type of fluid and laboratory.

How do I prepare for the test?

Preparation depends on the fluid being tested and the collection method. Follow the clinician or laboratory's instructions, and tell them about recent infections, medications, pregnancy, or other relevant medical conditions.

Reference range

Adult: 10-40 U/LN/A

Specimen: serum

No special preparation required. Avoid fatty meals before the test if possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Blast cell percentage, fluid

Frequently asked questions

What are blast cells?
Blast cells are immature precursor cells that normally mature into blood or immune cells. A small number can sometimes be present during normal cell turnover, depending on the fluid and clinical context.
Does an abnormal result mean I have cancer?
Not necessarily. An increased blast-cell proportion can have several causes, and additional testing is usually needed to distinguish a reactive process from a blood disorder.
Which fluid samples may be tested?
Depending on the clinical situation, the laboratory may test cerebrospinal, synovial, or another body fluid. The specific collection instructions are provided by the ordering clinician or laboratory.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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