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CD27 and CD19 B-cell Immunoglobulin (Ig) Subclass Quantification (Serum/Plasma)

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

This test measures levels of specific antibodies (immunoglobulins) and immune cell markers (CD27 and CD19) in your blood. It helps assess immune function, antibody responses, and potential immune deficiencies or disorders.

Quick summary

["This test evaluates key components of your immune system’s antibody production and immune cell activity."]

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

Key facts at a glance

LOINC
89358-6
Short code
CD27/CD19
Synonyms
CD27 Cells/Cells.CD19 NFr Bld
Category
chemistry
Sample
whole-blood
Container
EDTA (lavender-top) or ACD (yellow-top) anticoagulant tube; sodium heparin (green-top) tube is also acceptable for flow cytometry. Heparinized whole blood preferred when same-day processing is performed.
Units
N/A
Ref low
20
Ref high
50
Fasting
false
Population
adult
Sex
all
Age range
0–99 years
Method
Flow cytometry using fluorescently labeled monoclonal antibodies against CD27 and CD19 surface markers; results expressed as percentage of B lymphocytes (CD19+) co-expressing CD27
CPT
86356 (Monoclonal antibody flow cytometry, each cell surface marker); additional markers may be billed separately. Common panel billing includes 86355/86356/86357/86359/86360.
SNOMED
399247001 | Lymphocyte subset analysis (procedure); 408380003 | CD19+ B cell count (procedure)
Specimen volume
3-5 mL of whole blood for adults; minimum 1 mL for pediatric patients. Adequate sample volume is required to obtain sufficient events for reliable lymphocyte subset enumeration.
Stability
Specimen should be processed within 24-30 hours of collection when stored at room temperature (18-25°C). Refrigeration (2-8°C) is not recommended for optimal lymphocyte viability. If processing is delayed beyond 24 hours, viability and marker expression may be compromised.
Hemolysis max
0
Lipemia max
0
Icterus max
0
TAT
24–72 hours
Order
routine

What Does This Test Measure?

The test includes two main parts: measuring CD27 and CD19 markers on B cells (a type of white blood cell) and quantifying immunoglobulin (Ig) subclasses (IgG1, IgG2, IgG3, IgG4) in your serum or plasma. CD27 and CD19 are proteins involved in immune cell development and function, while IgG subclasses are types of antibodies that protect your body from infections.

Why Might This Test Be Ordered?

Your healthcare provider may order this test to evaluate immune function, diagnose conditions like chronic infections, autoimmune diseases, or immune deficiencies, or monitor treatment responses in patients with conditions affecting B cells or antibody production.

How Is the Test Performed?

A blood sample is drawn from a vein in your arm. The blood is then processed to separate serum or plasma, which is analyzed using advanced laboratory techniques to detect and measure CD27/CD19 markers and IgG subclasses.

What Does the Test Result Mean?

Results may show abnormal levels of CD27/CD19 markers or IgG subclasses, which can indicate immune system imbalances, reduced antibody production, or other underlying health issues. Your provider will interpret the results in the context of your medical history and symptoms.

Reference range

Reference values vary by laboratory and age. CD27 expression on CD19+ B cells is used to distinguish memory B cells (CD27+) from naive B cells (CD27-). Adult reference range for CD27+ memory B cells as a percentage of total CD19+ B cells is approximately 20-50%. Absolute counts should be interpreted with concurrent lymphocyte and CD19+ B cell counts.N/A

Specimen: whole-blood

No special patient preparation required. Fasting is not necessary. Recent vaccinations (especially within 4-6 weeks), acute infections, or immunosuppressive therapy may affect results and should be noted on the requisition. Specimen should be collected prior to administration of immunomodulatory agents when possible.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IgG Subclass and Immune Cell Marker Test

Frequently asked questions

Why do I need this test?
Your doctor may recommend this test to check how well your immune system is working, especially if you have symptoms like frequent infections, fatigue, or unexplained immune-related issues.
What do my test results mean?
Your results will be reviewed by a healthcare provider to determine if your immune system or antibody levels are within expected ranges. They may suggest additional tests or treatments if needed.
How often will I need this test?
The frequency depends on your health condition and treatment plan. Your doctor will let you know how often you should get retested.
  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