What is the Full Blood Count (5-Part Differential)?

The Full Blood Count (FBC) with 5-part white cell differential is one of the most commonly requested blood tests in clinical medicine. It measures the quantity, size and composition of red blood cells, white blood cells and platelets, providing a broad overview of blood and bone marrow function.

The 5-part differential breaks white blood cells into five distinct types, neutrophils, lymphocytes, monocytes, eosinophils and basophils, each with a specific role in immunity and inflammation. Analysing these subtypes offers deeper insight than a basic white cell count alone.

This test is used routinely for health screening, diagnosis, monitoring chronic disease and assessing acute illness.

Why do I need a Full Blood Count test?

You may need an FBC if you have symptoms such as fatigue, recurrent infections, bruising, or unexplained illness. It is also widely used as part of routine health checks, pre-operative assessments and chronic disease monitoring.

Because many medical conditions affect the blood before symptoms become severe, the FBC is a powerful early indicator of underlying issues, ranging from nutritional deficiencies to serious haematological disorders.

Symptoms and scenarios where testing is recommended:

• Persistent fatigue or weakness
• Frequent or recurrent infections
• Shortness of breath
• Pale skin or dizziness
• Easy bruising or bleeding
• Monitoring chronic illness
• Routine health screening
• Pre-operative or baseline assessment

What’s Tested in This Profile?

Red Blood Cell Markers

• Haemoglobin (HGB)
• Haematocrit (HCT)
• Red Cell Count (RCC)
• Mean Corpuscular Volume (MCV)
• Mean Cell Haemoglobin (MCH)
• Mean Cell Haemoglobin Concentration (MCHC)
• Red Cell Distribution Width (RDW)

Platelet Markers

• Platelet Count (PLT)
• Mean Platelet Volume (MPV)

White Blood Cells

• White Cell Count (WCC)

5-Part White Cell Differential

• Neutrophils (NEUT)
• Neutrophils % (NEUT%)
• Lymphocytes (LYMPH)
• Lymphocytes % (LYMPH%)
• Monocytes (MONO)
• Monocytes % (MONO%)
• Eosinophils (EOSIN)
• Eosinophils % (EOSIN%)
• Basophils (BASO)
• Basophils % (BASO%)

Benefits of the Full Blood Count Test

• Detects anaemia and iron-related disorders
  Identifies low haemoglobin and abnormal red cell indices.
• Assesses immune system activity
  White cell patterns help detect infection or immune dysfunction.
• Identifies inflammation and allergic responses
  Eosinophils and basophils provide allergy and inflammation insight.
• Evaluates bone marrow function
  Reflects blood cell production health.
• Screens for haematological disorders
  Supports detection of blood cancers and marrow conditions.
• Monitors chronic disease and treatment effects
  Tracks changes over time in response to illness or therapy.
• Assesses bleeding and clotting risk
  Platelet levels indicate bleeding or clotting tendency.
• Essential baseline and routine health test
  Used widely in preventive and diagnostic medicine.

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

1. Select your nearest UK clinic and book an appointment.
2. A clinician or phlebotomist collects a venous blood sample.
3. The sample is analysed using automated haematology analysers.
4. Results are delivered securely online.

Option 2 – Home or Hotel Phlebotomy (+£60)

1. Book a UK-wide home or hotel visit at a convenient time.
2. A trained phlebotomist collects your blood sample on-site.
3. The sample is transported to the laboratory.
4. Results are uploaded digitally without the need to travel.

Your Results Explained

Low Levels

• Low haemoglobin or red cells may indicate anaemia.
• Low white cells may suggest immune suppression or viral illness.
• Low platelets may increase bleeding risk.

Typical UK reference ranges vary, but examples include:

• Haemoglobin: ~120–180 g/L
• WCC: ~4.0–11.0 ×10⁹/L
• Platelets: ~150–400 ×10⁹/L

Normal Levels

Normal results indicate balanced blood production and immune function.
This suggests healthy bone marrow activity and circulation at the time of testing.

High Levels

• High white cells often reflect infection or inflammation.
• Elevated red cells may be linked to dehydration or lung disease.
• High platelets may occur with inflammation or iron deficiency.

Results are always interpreted alongside symptoms and clinical context.