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B-cell Lymphocyte Count (Absolute Count)

Published: August 9, 2026Updated: August 16, 2026

This test measures the number of B cells in your blood, which are a type of white blood cell important for immune function, including producing antibodies.

Quick summary

["B cells help your body fight infections and fight diseases like cancer."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
51335-8
Short code
CD19CD43BM
Synonyms
CD19+CD43+ Cells NFr Mar
Category
chemistry
Sample
serum
Container
Heparinized bone marrow aspirate collected in a sterile sodium heparin (green-top) tube for flow cytometry; EDTA (purple-top) tube may also be acceptable for some laboratories. Maintain sterility and transport at room temperature.
Units
N/A
Ref low
0
Ref high
1
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
Flow cytometry immunophenotyping using fluorescently labeled monoclonal antibodies against CD19 and CD43 surface markers, typically performed on fresh bone marrow aspirate specimens with multi-color panel analysis on a flow cytometer.
CPT
88184
SNOMED
444148008
Specimen volume
1-3 mL of bone marrow aspirate is typically sufficient; first-pull aspirate is preferred for accurate cellular representation.
Stability
Specimen should be processed within 24-48 hours of collection when stored at room temperature (18-25°C). Do not refrigerate or freeze. Viability and antigen expression may decline with prolonged storage.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

What Is a B-Cell Count Used For?

Doctors may order this test to evaluate your immune system, monitor conditions like chronic infections, autoimmune diseases, or cancers (e.g., lymphoma, leukemia). It can also help assess responses to treatments like chemotherapy or immune therapies.

How Is the Test Performed?

A small sample of blood is drawn from a vein, usually in your arm. The blood is then analyzed in a lab to count the B cells.

What Does a B-Cell Count Tell You?

A lower-than-expected count may indicate immune suppression, infections, or certain cancers. A higher-than-expected count could suggest overactive immune responses or certain blood disorders.

Factors That Can Affect Results

Recent infections, medications (like steroids or chemotherapy), or certain medical conditions (e.g., HIV, autoimmune diseases) can influence B-cell levels. Stress, diet, or timing of blood draw may also play a role.

Reference range

CD19+CD43+ cells are typically absent or present at very low frequency (<1%) in normal bone marrow. Reference ranges are laboratory-specific and should be interpreted in the context of the total B-cell population and clinical findings.N/A

Specimen: serum

No special patient preparation is typically required. Patients should inform their healthcare provider of any recent medications, including immunosuppressants or chemotherapy, which may affect results. Bone marrow aspiration is performed under local anesthesia with or without sedation.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

B-Cell Count

Frequently asked questions

Why might my doctor ask for this test?
Your doctor may request this test to diagnose or monitor conditions such as immune deficiencies, infections, or blood cancers. It can also help track how well treatments are working for conditions like lupus, rheumatoid arthritis, or HIV.
What are the normal ranges?
There are no specific numeric ranges provided here since they vary by lab and individual health. Your doctor will interpret results in the context of your overall health and medical history.
What should I do if my B-cell count is abnormal?
If your results are outside expected ranges, your doctor will discuss next steps, which may include further testing, adjustments to treatment, or additional monitoring. Always follow their guidance.
  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 16, 2026. · Read our editorial policy