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Absolute Count of CD19+ and CD20+ B-Cell Subsets in Peripheral Blood

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

This test measures the number of specific immune cells (CD19+ and CD20+) in your blood, which helps assess the health and function of your B-cell system, often used in monitoring conditions like lymphoma or immune disorders.

Quick summary

["This test helps track B-cell populations for diagnosis, treatment planning, or monitoring immune function."]

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

Key facts at a glance

LOINC
57397-2
Short code
CD19CD20BF
Synonyms
CD19+CD20+ Cells NFr Fld
Category
chemistry
Sample
serum
Container
Sterile, leak-proof container appropriate for body fluid collection; typically a sterile conical tube or vacuum collection device supplied by the laboratory. For CSF, use sterile cryovials. Anticoagulant (EDTA or heparin) may be required depending on laboratory protocol.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
0–120 years
Method
Flow cytometry using fluorescently labeled monoclonal antibodies against CD19 and CD20 surface markers
CPT
86355
SNOMED
1251674006
Specimen volume
Minimum 1-3 mL of body fluid depending on fluid type and laboratory requirements; 5 mL preferred for adequate cell yield and analysis. CSF typically requires 1-2 mL minimum.
Stability
Specimen should be processed within 1-2 hours of collection for optimal viability. If delayed processing is necessary, store at 2-8°C and analyze within 24 hours. Do not freeze.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
24–72 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you have symptoms or conditions that affect B-cells, such as infections, autoimmune diseases, or cancers like lymphoma. It may also be used before or during treatment to monitor immune response.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is processed to separate cells, and specific markers (CD19 and CD20) are identified using advanced laboratory techniques to count these B-cell subsets.

What to Expect Before the Test

No special preparation is needed, but inform your provider about any medications or conditions that could affect results. Avoid strenuous activity 24 hours before the test if possible.

What the Results Mean

Results show the absolute number of CD19+ and CD20+ cells per microliter of blood. Abnormal counts may indicate immune deficiencies, overactivity, or diseases like leukemia or lymphoma. Your provider will interpret results in the context of your overall health and medical history.

Reference range

Reference values are dependent on the specific body fluid type (e.g., cerebrospinal fluid, pleural fluid, peritoneal fluid, pericardial fluid, synovial fluid) and clinical context. B-lymphocyte subsets in body fluids are generally interpreted in conjunction with peripheral blood counts and clinical findings. Consult laboratory-specific reference ranges for the specific fluid type analyzed.N/A

Specimen: serum

No special patient preparation required. The specific body fluid must be collected by an appropriately trained healthcare professional using aseptic technique appropriate for the fluid type (e.g., lumbar puncture for CSF, thoracentesis for pleural fluid).

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

B-Cell Subset Counts

Frequently asked questions

How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on lab processing times and your healthcare provider’s workflow.
What does it mean if my B-cell counts are low?
Low counts of CD19+ or CD20+ B-cells may indicate an immune deficiency, where your body struggles to fight infections effectively. This could be due to genetic disorders, certain medications, or autoimmune conditions. Your provider will discuss further testing or interventions if needed.
Can lifestyle changes affect these test results?
While diet and exercise generally do not directly impact B-cell counts, chronic stress or poor sleep may indirectly affect immune function. Avoiding infections or illnesses before testing can help ensure accurate results, but lifestyle changes alone are unlikely to alter test outcomes significantly.
  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