Lymphocyte Subset Panel 1
Lymphocyte Subset Panel 1 is a blood test panel measuring key T, B, and NK cell subsets to help interpret immune patterns in context.
This panel bundles multiple biomarker tests in one order—your report explains how results fit together.
This is not a single “immune marker.” Lymphocyte Subset Panel 1 is a lab panel that counts and characterizes several types of white blood cells (lymphocytes) in the same blood draw—most commonly T cells, B cells, and natural killer (NK) cells, plus important T-cell subgroups. The value is in the pattern across the panel: which cell lines are low or high, whether changes are proportional, and whether the balance between helper and cytotoxic T cells looks typical for your situation.
Do I need this panel?
You might consider a lymphocyte subset panel if you are trying to make sense of recurrent infections (especially frequent sinus, bronchitis, or pneumonia episodes), slow recovery from common viruses, or infections that seem unusually severe for you.
This panel is also commonly used during autoimmune and inflammatory workups when symptoms are nonspecific—fatigue, joint pain, rashes, mouth ulcers, swollen glands, fevers without a clear cause—or when a screening test (like an ANA) raises questions but does not provide a diagnosis on its own.
Another reason to order this panel is medication monitoring. Some immune-modulating therapies (including certain biologics, chemotherapy, or long-term steroids) can shift lymphocyte counts and the CD4/CD8 balance. Knowing your baseline and tracking changes can help your clinician interpret risk and response.
Because this is a multi-marker panel, it is best used to support clinician-directed care rather than self-diagnosis. Your symptoms, exam, infection history, medications, and other labs (like immunoglobulins and inflammatory markers) determine what a “concerning” pattern means for you.
This panel is typically performed by flow cytometry, which identifies lymphocyte populations using cell-surface markers (CD markers) and reports absolute counts and/or percentages.
Lab testing
Order Lymphocyte Subset Panel 1 through Vitals Vault.
Schedule online, results typically within about a week
Clear reporting and optional clinician context
HSA/FSA eligible where applicable
Get this panel with Vitals Vault
Vitals Vault makes it straightforward to order Lymphocyte Subset Panel 1 and review your results in a way that keeps the full immune picture in view. Instead of focusing on one number, you can look at how T cells, B cells, and NK cells relate to each other and to your symptoms.
After your blood draw, you can use PocketMD to walk through your panel results, questions to ask your clinician, and what additional labs are commonly paired with lymphocyte subsets (for example, total immunoglobulins, inflammation markers, or autoimmune serologies when appropriate).
If you are trending results over time—after an infection, during treatment, or as part of an immunology evaluation—Vitals Vault helps you keep your prior panels organized so changes are easier to interpret.
- Single blood draw with multiple immune cell measurements
- Designed for pattern-based interpretation across the panel
- PocketMD support to reduce confusion and catastrophizing
- Useful for baseline testing and follow-up trending
Key benefits of Lymphocyte Subset Panel 1
- Shows whether low total lymphocytes are driven by T cells, B cells, NK cells, or a combination.
- Adds context to autoimmune workups by describing immune cell distribution rather than relying on a single screening antibody test.
- Helps interpret recurrent infection patterns when routine CBC results look “normal” but symptoms persist.
- Provides the CD4/CD8 balance, which can be clinically useful when immune activation or immune suppression is suspected.
- Supports medication monitoring when therapies can shift lymphocyte populations over time.
- Separates relative percentage changes from true absolute-count changes, which can prevent false reassurance or unnecessary alarm.
- Creates a baseline you can trend after major infections, treatment changes, or specialist evaluations.
What is the Lymphocyte Subset Panel 1 panel?
Lymphocyte Subset Panel 1 is a blood test panel that measures several major lymphocyte populations—your adaptive immune cells (T cells and B cells) and innate-like lymphocytes (natural killer cells). It is usually reported as both percentages of total lymphocytes and absolute counts (cells per microliter), because those two views can tell different stories.
The panel is typically run using flow cytometry. In plain language, the lab tags immune cells with fluorescent markers that bind to specific “CD” proteins on the cell surface (cluster of differentiation markers). The instrument then counts how many cells fall into each category.
The most common categories included are:
• T cells (CD3+): the broad T-cell population. • Helper T cells (CD4+): coordinate immune responses and help B cells make antibodies. • Cytotoxic T cells (CD8+): kill infected or abnormal cells. • B cells (CD19+ or CD20+): produce antibodies and support immune memory. • Natural killer (NK) cells (often CD16+/CD56+): respond quickly to infected or stressed cells.
Because these cell lines rise and fall for many reasons—recent infections, chronic inflammation, immune-suppressing medications, nutritional status, stress physiology, and some primary immune disorders—this panel is most informative when interpreted alongside your history and other labs.
What do my panel results mean?
Low patterns on a lymphocyte subset panel
A “low” pattern usually means one or more lymphocyte lines have low absolute counts (not just low percentages). If multiple lines are low (for example, low T cells and low B cells), clinicians think about broader immune suppression, recent severe viral illness, medication effects, bone marrow suppression, protein-calorie malnutrition, or less commonly an underlying immune deficiency. If the low pattern is selective—such as low CD4 T cells with relatively preserved CD8, B cells, and NK cells—the differential narrows and the next step is often to review medications, recent infections, and whether repeat testing is needed to confirm persistence. Low B cells can be seen after certain therapies that target B cells and may pair with low immunoglobulins; that combination is often more meaningful than either result alone.
Balanced (typical) patterns
An “optimal” or typical pattern is one where absolute counts and percentages for T cells, CD4 and CD8 subsets, B cells, and NK cells are within the lab’s reference ranges and the proportions make sense together (for example, no single population is disproportionately expanded or depleted). This does not rule out autoimmune disease, chronic infection, or immune dysregulation on its own—many immune conditions can exist with normal subset counts—but it can reduce concern for major quantitative lymphocyte deficiencies. When your symptoms persist despite a typical panel, clinicians often look to functional immune testing, antibody levels (IgG/IgA/IgM), vaccine response, inflammation markers, and targeted autoimmune testing rather than repeating subsets immediately.
High patterns on a lymphocyte subset panel
A “high” pattern can mean elevated absolute lymphocyte counts overall or expansion of a specific subset (for example, higher CD8 T cells or higher NK cells). This is often reactive—your immune system responding to a recent or ongoing infection, inflammation, smoking exposure, or physiologic stress. The pattern matters: a proportional rise across multiple subsets may simply track with a higher total lymphocyte count, while a disproportionate expansion of one lineage may prompt a clinician to consider chronic immune stimulation and, in some cases, whether additional evaluation is needed. Persistently high lymphocyte counts, especially with abnormal cells on a blood smear or unexplained symptoms (night sweats, weight loss, enlarged lymph nodes), should be reviewed promptly with a clinician.
Factors that influence lymphocyte subset results
Lymphocyte subsets are dynamic. Recent viral infections (including common respiratory viruses), vaccinations, and flares of inflammatory or autoimmune conditions can shift CD4, CD8, and NK cell distributions for weeks. Medications are a major driver: corticosteroids, chemotherapy, some biologics, and other immunosuppressants can lower counts; certain immune-stimulating states can raise them. Timing and context also matter—acute illness, poor sleep, intense exercise, and stress hormones can transiently change circulating lymphocyte numbers. Finally, interpretation depends on whether you are looking at percentages or absolute counts: a normal percentage can hide a low absolute count if your total lymphocytes are low, and a “low percentage” can occur even when absolute counts are fine if another population is expanded.
What’s included in this panel
- Absolute Cd19+ Cells
- Absolute Cd3+ Cells
- Absolute Cd4+ Cells
- Absolute Cd8+ Cells
- Absolute Lymphocytes
- Absolute Nk Cells (Cd16+Cd56+Cells)
- % Cd16+Cd56 (Natural Killer Cells)
- % Cd19 (B Cells)
- % Cd3 (Mature T Cells)
- % Cd4
- Cd4/Cd8 Ratio
- % Cd8
Frequently Asked Questions
Do I need to fast for Lymphocyte Subset Panel 1?
Fasting is usually not required for a lymphocyte subset panel because it measures immune cell populations rather than glucose or lipids. If you are combining this panel with other labs that do require fasting, follow the instructions for the combined order.
Why does this panel report both percentages and absolute counts?
Percentages show how your lymphocytes are distributed (the “mix” of T, B, and NK cells). Absolute counts show how many cells are actually present in your blood. A percentage can look normal even when the absolute count is low if your total lymphocytes are low, so clinicians often rely heavily on absolute counts for risk assessment.
How should I read the CD4/CD8 ratio on a panel like this?
The CD4/CD8 ratio summarizes the balance between helper (CD4) and cytotoxic (CD8) T cells. A ratio that is higher or lower than the reference range can be seen with recent infections, chronic inflammation, immune suppression, or immune activation. The ratio is most meaningful when you also look at the underlying CD4 and CD8 absolute counts rather than the ratio alone.
Can a normal lymphocyte subset panel rule out autoimmune disease?
No. Many autoimmune conditions do not cause major changes in lymphocyte subset counts, especially early on. This panel is better at describing immune cell quantity and balance than diagnosing a specific autoimmune disease. It is often interpreted alongside symptoms, inflammatory markers, and targeted autoantibodies when appropriate.
What if my results are abnormal but I feel fine?
Mild shifts can be temporary and may reflect recent infections, vaccines, stress, or medications. The next step is usually to review timing and context, confirm whether the abnormality is in absolute counts versus percentages, and decide with your clinician whether repeat testing or additional immune labs (like immunoglobulins) are appropriate.
Is this panel useful for recurrent sinus or respiratory infections?
It can be. If you have frequent sinopulmonary infections, this panel helps determine whether low T cells, low B cells, or low NK cells might be contributing. It is commonly paired with total immunoglobulins (IgG, IgA, IgM) and sometimes IgG subclasses or vaccine response testing, depending on your history.
Is it better to order this as a panel rather than ordering individual tests?
For lymphocyte subsets, ordering a panel is typically more coherent because the results are meant to be interpreted together (for example, CD4 and CD8 counts plus their ratio, alongside B and NK cells). A panel also reduces the chance of missing a key companion measurement that changes the interpretation.