Laboratory Test Overview: What This Test Is, How the Sample Is Collected, and Why It Is Ordered
A bone marrow test that measures immature basophils and white blood cells to evaluate bone marrow function and diagnose blood disorders.
{"This test examines immature basophils (band form) and other white blood cells in your bone marrow","It helps diagnose leukemia, bone marrow disorders, and unexplained blood abnormalities","Sample is collected via bone marrow aspiration or biopsy, typically from the hip bone"}
Key facts at a glance
- LOINC
- 50658-4
- Short code
- BASO-BAND BM
- Synonyms
- Basophils band NFr Mar
- Category
- chemistry
- Sample
- serum
- Container
- EDTA lavender-top tube (bone marrow aspirate) and serum separator tube (SST) for serum
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 18 years
- Method
- Microscopic differential cell count with Wright-Giemsa or May-Grünwald-Giemsa stained bone marrow aspirate smear evaluation
- CPT
- 85097
- SNOMED
- 312149006
- Specimen volume
- 1-3 mL bone marrow aspirate; 1-2 mL serum
- Stability
- Bone marrow aspirate slides should be prepared and stained within 2 hours of collection; serum stable for 24 hours at room temperature, 7 days at 2-8°C
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
This test is a laboratory analysis that measures specific substances in your sample to help your healthcare provider evaluate how your body is working. The results can reveal important information about your overall health, help detect certain conditions early, and guide decisions about any treatment you may need.
The Basophils (Band Form) and Leukocytes in Bone Marrow test is a specialized laboratory test that examines your bone marrow sample to count and analyze immature basophils (called band forms) and other white blood cells. Basophils are a type of white blood cell that play an important role in your immune system, particularly in allergic reactions and fighting parasites. The 'band form' refers to immature basophils that are still developing.
A trained healthcare professional will collect your sample during a quick office or laboratory visit. For a blood sample, a small needle is gently inserted into a vein, usually in your arm, and the blood is drawn into a sealed tube. For a urine sample, you will receive a sterile container and simple instructions. Collection takes only a few minutes, and you can usually return to your normal activities right away.
A small sample of bone marrow is collected via a procedure called bone marrow aspiration (liquid sample) or biopsy (small tissue sample). This is usually taken from the hip bone (iliac crest) or occasionally from the breastbone. The area is numbed with local anesthesia, and a special needle is used to withdraw the marrow. Although the procedure may cause some discomfort, it is generally well-tolerated.
Your doctor may order this test to check for signs of illness, investigate symptoms you have been experiencing, screen for conditions before they cause problems, or monitor how well an existing treatment is working. The results help your care team make accurate diagnoses and choose the safest, most effective plan for you.
Your healthcare provider may order this test if you have unexplained abnormalities in your blood tests, symptoms of a blood disorder, or suspicion of conditions affecting your bone marrow. It helps doctors evaluate how well your bone marrow is producing blood cells and identify any abnormal cell development.
Reference range
Band form basophils are extremely rare in normal bone marrow; basophilic band forms are not typically reported as a percentage in standard bone marrow differential counts. Reference is established by individual laboratory hematopathology review.N/A
No special patient preparation required prior to bone marrow aspiration. Bone marrow collection is performed by a trained physician under local anesthesia (typically posterior iliac crest). No fasting required for serum component.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Frequently asked questions
How long does it take to get results?
Does the test hurt?
Are there any risks from the bone marrow procedure?
Do I need to fast before this test?
Sources
- 1
- 2
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 16, 2026. · Read our editorial policy