Skip to content

B-cell CD19 and CD38 Expression in Peripheral Blood Cells (Flow Cytometry)

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

This test measures the presence and proportion of B-cells expressing CD19 and CD38 markers in your blood, often used to evaluate immune cell function or detect abnormalities.

Quick summary

["Assessing immune cell health through specific protein markers in your blood sample."]

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

Key facts at a glance

LOINC
57395-6
Short code
CD19CD38BF
Synonyms
CD19+CD38+ Cells NFr Fld
Category
chemistry
Sample
serum
Container
Sterile, leak-proof container appropriate for the specific body fluid type (e.g., sterile cryogenic vial for CSF, sterile collection tube for pleural/peritoneal fluid). Anticoagulant may be required depending on fluid type.
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Flow cytometry using fluorescently labeled monoclonal antibodies (CD19-FITC, CD38-PE) for immunophenotyping of lymphocyte subsets in body fluid specimens
CPT
86355
SNOMED
121781000
Specimen volume
Minimum 1-2 mL of body fluid; optimal volume 3-5 mL depending on fluid type and cell count. Larger volumes may be required for fluids with low cellularity such as cerebrospinal fluid.
Stability
Specimens should be processed within 4-6 hours of collection for optimal cell viability. If processing is delayed, specimens should be maintained at room temperature (18-25°C). Refrigeration may decrease cell viability and is generally not recommended.
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

The test identifies B-cells, a type of white blood cell involved in immune responses. CD19 is a marker found on nearly all B-cells, while CD38 is another protein that appears on activated B-cells. Flow cytometry analyzes these markers to count and characterize the cells.

Why It’s Done

Doctors may order this test to diagnose or monitor conditions like chronic lymphocytic leukemia (CLL), lymphoma, or other immune-related disorders. It can also help track responses to treatments that target B-cells.

Sample Collection and Preparation

A small blood sample is drawn from a vein, typically in your arm. The sample is processed to isolate blood cells, which are then analyzed for CD19 and CD38 expression under a microscope using flow cytometry.

Preparation and Timing

No special preparation is needed, but fasting is not required. Results may take several days to weeks, depending on lab workload and clinical urgency.

Reference range

Reference ranges vary by body fluid type, clinical context, and laboratory methodology. Results should be interpreted in conjunction with clinical findings and compared to institution-specific reference ranges. Typically reported as percentage of total lymphocytes or absolute count per microliter.N/A

Specimen: serum

No special patient preparation is required prior to specimen collection. Inform the laboratory of any current immunosuppressive therapy, recent blood transfusions, or hematopoietic stem cell transplantation, as these may affect results.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

B-Cell Marker Analysis

Frequently asked questions

What does a positive or abnormal result mean?
An abnormal result may signal an immune disorder, such as a type of leukemia or lymphoma, or could reflect immune activation. Your doctor will interpret results in the context of your symptoms and medical history.
Will I need to prepare for this test?
No special preparation is needed. However, inform your doctor about any medications or conditions that might affect blood cell counts.
How long will it take to get my results?
Results typically take 3–10 business days, depending on lab processing times. Your healthcare provider will discuss findings with you.
  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