Lymphocyte Subsets
This test measures key lymphocyte populations in the blood. It provides detailed insight into immune system function and balance.
Turnaround time
2 days
Biomarkers count
1
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Details about Lymphocyte Subsets
What is the Lymphocyte Subsets Test?
The Lymphocyte Subsets test is a specialised blood test that measures different types of lymphocytes, a group of white blood cells essential for immune defence. Using flow cytometry, the test identifies and quantifies specific immune cell populations based on surface markers.
The main lymphocyte subsets assessed include T lymphocytes (CD3), helper T cells (CD4), cytotoxic T cells (CD8), B lymphocytes (CD19) and natural killer (NK) cells (CD16/CD56). Evaluating these subsets provides a detailed picture of immune competence and regulation.
This test is widely used in immunology, infectious disease and haematology to investigate immune deficiency, immune activation and treatment effects.
Why do I need a test for Lymphocyte Subsets?
You may need this test if there is concern about immune system dysfunction, recurrent infections or unexplained inflammatory or autoimmune conditions. Changes in lymphocyte populations can indicate immune suppression, immune activation or imbalance.
The test is also essential for monitoring conditions that directly affect immune cells and for assessing response to treatments that influence immune function.
Symptoms and scenarios where testing is recommended:
- Recurrent or unusual infections
- Suspected immune deficiency
- Chronic viral infections
- Monitoring immunosuppressive therapy
- Autoimmune or inflammatory disorders
- Unexplained lymphopenia or lymphocytosis
- Post-transplant immune monitoring
- HIV or other immune-related assessments
Benefits of the Lymphocyte Subsets Test
- Detailed immune system profiling
Goes beyond a standard white cell count. - Identifies immune deficiencies
Detects reduced or abnormal lymphocyte populations. - Assesses immune activation or suppression
Helps evaluate immune balance. - Supports infection risk assessment
Identifies vulnerability to opportunistic infections. - Monitors immune-modulating treatments
Useful during chemotherapy or immunosuppression. - Guides further immunological testing
Helps direct targeted investigations. - Clinically established diagnostic tool
Widely used in specialist care. - Supports long-term immune monitoring
Tracks immune changes over time.
Step-by-Step: How Testing Works
Choose your preferred testing method
You can attend one of our UK partner clinics or arrange a home or hotel visit with a mobile phlebotomist.
Option 1 – In-Clinic Blood Draw
- Select your nearest UK clinic and book an appointment.
- A clinician or phlebotomist collects a venous blood sample.
- The sample is analysed using flow cytometry.
- Results are delivered securely online.
Option 2 – Home or Hotel Phlebotomy (+£60)
- Book a UK-wide home or hotel visit at a convenient time.
- A trained phlebotomist collects your blood sample on-site.
- The sample is transported to the laboratory.
- Results are uploaded digitally without the need to travel.
Your Results Explained
Low Levels
Low levels of specific lymphocyte subsets may indicate immune deficiency, bone marrow suppression or effects of medication.
Reduced CD4 cells, for example, can increase susceptibility to infections.
Typical UK reference ranges vary by subset and laboratory.
Normal Levels
Normal lymphocyte subset distribution suggests balanced and functional immune activity.
This supports effective immune defence and regulation.
High Levels
Elevated lymphocyte subsets may reflect immune activation, chronic infection or inflammatory conditions.
Further investigation may be required depending on clinical context.
How It Works
Simple steps to get your results
Book Online
Choose your test online and book in seconds. Select your preferred clinic location or home visit option.
Visit or Test at Home
Attend one of our UK or London clinics, arrange a home nurse visit, or use a finger-prick kit where available.
Get Your Results
Your sample is analysed by accredited UK laboratories, with secure results delivered directly to you.
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WhatsApp UsHow to Prepare for Your Test
Follow these guidelines for accurate results
Sample Timing
Where possible, attend your blood test between 7am and 12pm. Please wait until any short-term illness or infection has fully resolved before testing. Avoid intense exercise for 24–48 hours beforehand, as this can affect certain markers.
Fasting & Hydration
Fasting is not always required, but some tests may recommend it. If fasting is advised, avoid food for 8–12 hours before your appointment and drink water only. Stay well hydrated, as this helps with sample collection and accuracy.
Medications & Supplements
Continue prescribed medications unless advised otherwise by your clinician. Avoid vitamin, mineral, or biotin supplements for at least 24–48 hours before your test, as these can interfere with results. If you are unsure about any medication or supplement, please let us know before your appointment.
Hormones & Menstrual Cycle
For hormone-related tests, timing within your menstrual cycle may be important. If relevant, follow any specific guidance provided on your test page.
If you have any questions or special circumstances, our team is happy to advise before your appointment.