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Blasts Assessment, Bone Marrow Fluid

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

A bone marrow test that evaluates immature white blood cells called blasts, often to help diagnose or monitor leukemia and lymphoma.

Quick summary

["This test assesses the number and appearance of immature blood cells in bone marrow fluid."]

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

Key facts at a glance

LOINC
107058-0
Short code
Blasts assessmnt Mar FC
Synonyms
Blasts assessmnt Mar FC
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
Method
flow-cytometry
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?

A blast is an immature blood cell that normally develops into a mature white blood cell. Blast assessment examines a bone marrow sample to determine how many blasts are present and whether they look normal or abnormal.

Why might I need this test?

This test may be used to investigate unexplained low blood counts, evaluate suspected leukemia or lymphoma, and monitor treatment or remission. It is often interpreted together with other bone marrow, blood, and flow-cytometry results.

How is the test performed?

A clinician removes a small amount of bone marrow fluid, usually from the hip bone. Laboratory professionals prepare and examine the sample microscopically to assess the blast cells; additional specialized tests may sometimes be performed.

How do I prepare for the test?

No special preparation is usually required for the laboratory assessment itself. The bone marrow procedure involves local anesthetic and may cause brief pressure or soreness at the collection site; follow your clinician's instructions about medicines and activity.

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

Bone Marrow Blast Assessment

Frequently asked questions

What are blast cells?
Blasts are immature white blood cells. A small number can normally be found in bone marrow, while an increased proportion may be associated with leukemia or another blood-forming disorder.
Is bone marrow blast assessment the same as a complete blood count?
No. A complete blood count measures cells in circulating blood, while a bone marrow blast assessment directly evaluates immature cells in a bone marrow sample.
Does this test require surgery or general anesthesia?
No. Bone marrow is usually collected with a needle under local anesthetic. You may experience brief pressure or soreness during and after the procedure.
  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