When visiting a doctor for a health checkup, the first test they often recommend is a full blood count. Also called a complete blood picture or complete blood count (CBC), it is one of the most common tests used to monitor and diagnose health conditions.
This simple test can help identify signs of anaemia and certain infections. It can also help study the effects of medications on your health.
Read more to understand how a full blood examination provides a deep view of what’s happening inside your body, how much it costs, and how to check if your blood reports are normal.
What Is a Full Blood Count?
A full blood count is a laboratory test that analyses your blood sample and measures the number, size, and health of the different blood cells.
These include the components:
- Red blood cells (RBCs)
- White blood cells (WBCs)
- Platelets
- Hemoglobin
- Several related indices that describe cell size and quality
This test provides crucial insights to doctors because blood reveals a lot about what’s happening across your multiple health systems, such as immune function, oxygen delivery, clotting, inflammation, and even bone marrow health.
Why Is a Full Blood Count Test Done?
Whether you’re experiencing unexplained tiredness or complications such as infections, anaemia, or immune problems, a full blood examination is the first clue to identifying the underlying cause.
It doesn’t diagnose everything on its own, but gives an idea to your doctor in deciding what to look at next.
Some common reasons this test is needed for are:
- Routine health check-ups
- Constant fatigue or weakness
- Fever or suspected infection
- Unexplained weight loss or night sweats
- Bleeding or Frequent bruising
- Monitoring chronic illnesses
- Checking how medications are affecting your body
- Assess health during pregnancy
- Before or after surgery
In short, if there is any health issue, this is often the first test you’ll need. It can help identify abnormalities early, after which further tests can pinpoint the underlying issues.
Now that you know what a full or complete blood picture test means, let’s take a look at the various parameters that it covers.
Full Blood Count Parameters
To fully understand your blood report, the doctors need to analyse your full/complete blood count parameters. According to NCBI, these are:
1. Red Blood Cell (RBC) Count
Red blood cells are responsible for carrying oxygen throughout your body. When their values are off, you may experience fatigue and shortness of breath. Your providers may look at:
- RBC (Red Blood Cell Count): The number of red blood cells per microlitre (mcL) of blood. A drop of blood is typically 40-50 mcL.
- Haemoglobin (Hb): This is the main protein that carries oxygen inside RBCs.
- Hematocrit (Hct): This tells the percentage of blood that RBCs make.
Additional RBC indices can help describe the following details:
- Mean Corpuscular Volume (MCV): Average size/volume of RBCs
- Mean Corpuscular Haemoglobin (MCH): Amount of haemoglobin (weight) per RBC
- Mean Corpuscular Haemoglobin Concentration (MCHC): Check the average haemoglobin concentration in RBCs
- Red cell distribution width (RDW): It tells about the variation in RBC size (all close to the same size or have significant size differences
These values help determine the type of anaemia, if present.
2. White Blood Cell (WBC) Count and Differentials
White blood cells protect your body against infections and foreign invaders like microorganisms, allergens, and toxins.
The doctor may order a blood test with only a total white blood cell count or with a differential. A differential counts the different types of white blood cells and immature red blood cells. The count is denoted as an absolute (“as”) or a percentage (%) of all of your white blood cells.
- Total WBC count: Overall immune cell count
- Neutrophils: These are the first to combat bacterial and fungal infections.
- Lymphocytes: As the key players in viral immunity, they remember prior infections, providing immunity against the same viral types in the future.
- Monocytes: These clean-up cells during infections and alert the immune system when bacteria or viruses enter your body.
- Eosinophils: These are the WBC that fight allergies and parasites.
- Basophils: These are WBCs that produce histamine during allergic reactions and heparin to prevent blood clotting.
- Immature granulocytes: These are early-stage/immature neutrophils, eosinophils or basophils.
- Nucleated red blood cells (nRBC): The nRBC count includes immature red blood cells; the total number is expressed as absolute nRBCs or as a percentage of RBCs per 100 WBCs.
A CBC with a differential gives a deeper immune picture.
3. Platelet Count
Platelets are responsible for clotting and wound healing. The results show these parameters:
- Platelet count: Number of platelets in blood
- MPV (Mean Platelet Volume): Average platelet size
Too many or too few platelets can increase the risk of bleeding or clotting.
Full Blood Count Normal Ranges (Adults)
Once your blood test results are ready, compare them against the reference ranges to determine whether your parameter count is low, normal, or high.
Here is the reference range for adults, given below to put your report into context:
| Test | Normal value for adults |
| RBC | 4.0 to 5.4 million cells per mcL (for females or those taking estrogen) or 4.5 to 6.1 million cells per mcL (for males or those taking testosterone) |
| WBC | 4,000 to 10,000 cells per mcL |
| Hct | 36% to 48% (for females or those taking estrogen) or 40% to 55% (for males or those taking testosterone) |
| MCV | 80 to 100 fL (femtoliters) |
| Hb | 11.5 to 15.5 g/dL (for females or those taking estrogen) or 13 to 17 g/dL (for males or those taking testosterone) |
| MCHC | 32 to 36 g/dL (grams per deciliter) |
| RDW | 12% to 15% |
| MCH | 27 to 31 pg (picograms) per cell |
| Lymphocytes | 1,000 to 4,800 per mcL |
| MPV | 7.0 fL to 9.0 fL |
| Platelet count | 150,000 to 400,000 cells per mcL |
| Neutrophils | 2,500 to 7,000 per mcL |
| Basophils | Less than 300 per mcL |
| Monocytes | 200 to 800 per mcL |
| Eosinophils | Less than 500 per mcL |
| NRBC | Less than 10 mcL |
| Immature granulocytes | Less than 100 mcL (0.1 k/mcL) |
Note: The normal ranges for the complete blood count can vary slightly by laboratory, age, sex, and clinical context. Always compare your values with the reference range printed on your report, not a random number online.
What Do Abnormal Results Mean?
If your CBC results are off the reference range, it’s called abnormal results. It does not always mean something serious. Most of the time, it indicates common health conditions that are treatable with supplements, diet, and medication, depending on underlying conditions.
Abnormal CBC reveal various health conditions as listed below:
Low Red Blood Cells or Haemoglobin
- Iron deficiency
- Chronic kidney disease
- Vitamin B12 or folate deficiency
- Bone marrow issues
- Blood loss
High Red Blood Cells
- Lung or heart conditions
- Sleep apnea
- Dehydration
High White Blood Cell Count
- Infection
- Inflammation
- Stress
- Certain blood disorders
- Allergies
Low White Blood Cell Count
- Viral infections
- Medications
- Autoimmune conditions
- Bone marrow suppression
Abnormal Platelets
- Infections
- Nutritional deficiencies
- Immune conditions
- Certain cancers
Note: Doctors interpret CBC values alongside symptoms, not in isolation. Always consult your doctor to determine whether your lab results are normal or abnormal.
Do You Need to Prepare for a Full Blood Count?
Usually, no prior preparation is required for a full blood count:
- You can eat and drink normally
- You can take your regular medications
However, if other tests are done at the same time, your doctor may give additional instructions, so always consult your healthcare provider for pre-test guidelines.
Full Blood Count Test Price in India
The full blood count test is relatively affordable, but costs may vary based on your location and whether it’s a home sample collection, in-lab testing, or a differential count.
On average, it is:
- ₹200 to ₹600 at local diagnostic labs
- ₹300 to ₹800 at hospitals or premium labs
How Long Does It Take to Get Results?
Most labs deliver CBC full blood count results within 24 hours. Some advanced labs provide reports within a few hours.
Your doctor will explain the results and advise whether further testing or treatment is needed.
Does a Complete Blood Count Test Detect Everything?
The blood test can provide information on blood cell deformity, irregularities, or count, and can also indicate your immune status, but it cannot confirm a diagnosis on its own; for that, you need further clinical evaluation.
For example:
- It does not directly test kidney or liver function
- It does not confirm cancer on its own
- It does not replace imaging or specialised tests
But it often serves as the starting point for further investigations.
When Should You Worry About Your Results?
You should speak to your doctor if:
- Values are significantly outside normal ranges
- Symptoms persist or worsen
- You have a chronic illness or are on long-term medication
- Multiple parameters are abnormal together
Never self-diagnose based solely on numbers.
Read More: Blood Transfusion Procedure: Everything You Need to Know
To Sum Up
A full blood count is one of the most common tests that can provide insights into your immunity, oxygen supply in the blood (via haemoglobin), clotting ability, inflammation, and how well your body is coping.
Do not self-diagnose based solely on blood test results; always consult a doctor for personalised guidance.
Frequently Asked Questions Related to Full Blood Count
What does a complete blood count test for?
It checks red blood cells, white blood cells, and platelets to assess overall health and detect conditions such as anaemia, infection, or clotting disorders.
What is the normal blood count for a child?
Children’s normal ranges vary by age, but generally WBC: 5,000-14,500/µL, RBC: 4.1-5.5 million/µL, Hb: 11-14 g/dL.
What is an alarming blood count?
Excessively high or low values, such as WBC above 30,000/µL or platelets below 20,000/µL. It can indicate serious health issues requiring immediate attention.
What illnesses can be diagnosed with a complete blood count?
CBC can help detect anaemia, infections, blood cancers, clotting disorders, and monitor chronic diseases or medication effects.
What is the normal range for a full blood cell count?
For adults: 4,000 to 10,000 cells per mcL, RBC 4.0 to 5.4 million cells per mcL (for females); 4.5 to 6.1 million cells per mcL (for males), Hb 11.5 to 15.5 g/dL, platelets 150,000 to 400,000 cells per mcL.
