Complete blood count normal value and it’s changes
complete blood count CBC normal reference values
CBC changes in disease anemia leukocytosis thrombocytopenia
complete blood count CBC reference ranges table
| Parameter | Normal Values | ↑ Increased | ↓ Decreased |
|---|---|---|---|
| Hemoglobin (Hgb) | Males: 13.5–17.5 g/dL; Females: 12.0–15.5 g/dL | Polycythemia, dehydration, high altitude, heavy smoking | Anemia (any cause), blood loss, hemodilution |
| Hematocrit (Hct) | Males: 41–53%; Females: 36–46% | Same as Hgb | Same as Hgb |
| RBC Count | Males: 4.5–5.9 × 10⁶/µL; Females: 4.0–5.2 × 10⁶/µL | Polycythemia vera, high altitude | Anemia, bone marrow failure |
| MCV (Mean Cell Volume) | 80–100 fL | Macrocytic anemia (B12/folate deficiency, alcohol, liver disease, hypothyroidism) | Microcytic anemia (iron deficiency, thalassemia, sideroblastic anemia) |
| MCH (Mean Cell Hemoglobin) | 27–33 pg | Macrocytosis | Hypochromic anemia |
| MCHC (Mean Cell Hgb Concentration) | 32–36 g/dL | Hereditary spherocytosis | Iron deficiency, thalassemia |
| RDW (RBC Distribution Width) | 11.5–14.5% | Mixed deficiency anemia, early iron/B12 deficiency | Not clinically significant |
Note: Physiologic factors including age, sex, pregnancy, smoking, and altitude significantly affect RBC parameters. High-normal hemoglobin is seen in smokers due to CO displacing O₂ in hemoglobin binding. (Harrison's, p. 1751)
| Parameter | Normal Values | ↑ Increased (causes) | ↓ Decreased (causes) |
|---|---|---|---|
| Total WBC | 4,500–11,000 /µL | Infection, inflammation, leukemia, corticosteroids, stress | Bone marrow suppression, chemotherapy, aplastic anemia, viral infections (HIV) |
| Neutrophils | 50–70% (2,500–7,500/µL) | Bacterial infection, MI, burns, steroids, CML | Aplastic anemia, chemotherapy, sepsis (overwhelming), autoimmune |
| Lymphocytes | 20–40% (1,500–4,500/µL) | Viral infections (EBV, CMV), CLL, ALL | HIV/AIDS, corticosteroids, radiation |
| Monocytes | 2–8% (200–800/µL) | TB, infective endocarditis, malaria, monocytic leukemia | Hairy cell leukemia, aplastic anemia |
| Eosinophils | 1–4% (100–400/µL) | Allergies, asthma, parasitic infections, Addison's, CML | Cushing's syndrome, acute stress |
| Basophils | 0–1% (0–100/µL) | Allergic reactions, CML, myeloproliferative disorders | Hyperthyroidism, acute infections |
| Bands | 0–5% | Bacterial infection, sepsis ("left shift") | — |
| Parameter | Normal Values | ↑ Thrombocytosis | ↓ Thrombocytopenia |
|---|---|---|---|
| Platelet Count | 150,000–400,000/µL | CML, iron deficiency, post-splenectomy, reactive inflammation, essential thrombocythemia | ITP, TTP, HUS, DIC, heparin-induced (HIT), bone marrow failure, hypersplenism |
| MPV (Mean Platelet Volume) | 7.5–12.5 fL | Increased platelet turnover (ITP), myeloproliferative disorders | Bone marrow failure |

| Type | MCV | Conditions |
|---|---|---|
| Microcytic | < 80 fL | Iron deficiency, thalassemia, sideroblastic anemia, chronic disease (sometimes) |
| Normocytic | 80–100 fL | Acute blood loss, chronic disease, hemolytic anemia, aplastic anemia, renal failure |
| Macrocytic | > 100 fL | B12/folate deficiency, alcohol, liver disease, hypothyroidism, medications (methotrexate, hydroxyurea) |
| Factor | Effect |
|---|---|
| High altitude | ↑ Hgb, Hct, RBC (compensatory erythrocytosis) |
| Smoking | ↑ Hgb (CO shifts O₂ dissociation curve) |
| Pregnancy | ↓ Hgb/Hct (dilutional), ↑ WBC, ↑ platelets may vary |
| Age (neonates) | ↑↑ Hgb (fetal Hgb), higher MCV |
| Age (elderly) | Mild ↓ Hgb; WBC response may be blunted |
| Female sex | Lower Hgb/Hct reference range due to menstrual losses |
If increased and decreased according to this normal values, make diagnosis
CBC abnormal values differential diagnosis hemoglobin WBC platelet changes
leukocytosis leukopenia neutrophilia lymphocytosis eosinophilia diagnosis
| Change | Diagnosis / Condition |
|---|---|
| ↑ Increased | Polycythemia vera, secondary erythrocytosis (high altitude, COPD, heavy smoking), dehydration (relative polycythemia) |
| ↓ Decreased | Anemia — iron deficiency, B12/folate deficiency, hemolytic anemia, aplastic anemia, chronic kidney disease, chronic blood loss, thalassemia, malignancy |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Increased | Polycythemia vera, erythrocytosis (altitude, smoking, cardiac/pulmonary disease) |
| ↓ Decreased | All types of anemia, bone marrow failure, hemolysis, blood loss, B12/folate deficiency |
| Change | Diagnosis / Condition |
|---|---|
| ↑ >1.05 (Hyperchromic) | B12 deficiency anemia, folate deficiency anemia (megaloblastic) |
| ↓ <0.85 (Hypochromic) | Iron deficiency anemia, thalassemia, sideroblastic anemia, chronic disease anemia |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Reticulocytosis | Hemolytic anemia (active destruction), post-hemorrhagic anemia (recovery phase), response to iron/B12/folate therapy |
| ↓ Reticulocytopenia | Aplastic anemia, bone marrow failure, pure red cell aplasia, B12/folate deficiency (ineffective erythropoiesis) |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Increased | Megaloblastic anemia (B12/folate deficiency), macrocytic anemia |
| ↓ Decreased | Iron deficiency anemia, thalassemia, hypochromic anemia |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Thrombocytosis (>320) | Reactive: infection, iron deficiency, post-splenectomy, inflammatory disease, malignancy; Primary: Essential thrombocythemia, CML |
| ↓ Thrombocytopenia (<180) | ITP (immune thrombocytopenic purpura), TTP, DIC, hypersplenism, bone marrow failure, aplastic anemia, drug-induced (heparin → HIT), viral infections (HIV, EBV), SLE |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Leukocytosis (>9.0) | Bacterial infection, inflammation, leukemia (CML/ALL/AML), corticosteroids, physiologic stress, burns, MI |
| ↑↑ Very high (≥30–50 × 10⁹) | Leukemoid reaction or Leukemia (CML) (Harrison's, p. 1805) |
| ↓ Leukopenia (<4.0) | Viral infections (influenza, HIV, EBV), aplastic anemia, SLE, B12/folate deficiency, chemotherapy, radiation, typhoid |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Increased ("Left Shift") | Acute bacterial infection, sepsis, abscess, pneumonia, appendicitis |
| ↓ Decreased | Bone marrow suppression, viral infections |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Neutrophilia | Bacterial infections, acute inflammation, MI, burns, corticosteroids, smoking, CML, stress/exercise |
| ↓ Neutropenia | Aplastic anemia, SLE, typhoid, brucellosis, viral infections, chemotherapy, agranulocytosis, B12 deficiency (hypersegmented neutrophils) |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Eosinophilia | Allergic diseases (asthma, urticaria, allergic rhinitis), parasitic infections (helminths), drug hypersensitivity, Löffler's syndrome, Addison's disease, eosinophilic leukemia, CML |
| ↓ Eosinopenia | Cushing's syndrome, acute bacterial infections, corticosteroid use, acute stress |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Basophilia | CML (hallmark), myeloproliferative disorders, allergic reactions, hypothyroidism, ulcerative colitis |
| ↓ Decreased | Hyperthyroidism, acute infections, Cushing's syndrome, anaphylaxis |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Lymphocytosis | Viral infections (EBV/mononucleosis, CMV, HIV, rubella, hepatitis), CLL (chronic lymphocytic leukemia), ALL, whooping cough (pertussis), TB |
| ↓ Lymphopenia | HIV/AIDS, corticosteroids, radiation, SLE, chemotherapy, bone marrow failure, immunodeficiency states |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Monocytosis | TB, infective endocarditis, malaria, brucellosis, sarcoidosis, monocytic leukemia (CMML), recovery phase of agranulocytosis |
| ↓ Monocytopenia | Aplastic anemia, hairy cell leukemia, corticosteroid use |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Elevated ESR | Infection/inflammation, TB, rheumatoid arthritis, SLE, malignancy, multiple myeloma, anemia, pregnancy |
| ↓ Very low ESR | Polycythemia vera, sickle cell anemia, congestive heart failure, cachexia |
| Change | Diagnosis / Condition |
|---|---|
| ↑ Increased | Polycythemia vera, dehydration, erythrocytosis (altitude, smoking) |
| ↓ Decreased | All types of anemia, blood loss, overhydration, pregnancy |
| CBC Pattern | Most Likely Diagnosis |
|---|---|
| ↓ Hgb + ↓ RBC + ↓ Colour Index + ↓ MCH | Iron Deficiency Anemia |
| ↓ Hgb + ↑ Colour Index + ↑ MCH + ↓ Reticulocytes | Megaloblastic Anemia (B12/Folate) |
| ↓ Hgb + ↑ Reticulocytes + normal/↑ Colour Index | Hemolytic Anemia |
| ↓ Hgb + ↓ WBC + ↓ Platelets (pancytopenia) | Aplastic Anemia |
| ↑↑ WBC + ↑ Neutrophils (left shift) | Bacterial Infection / Sepsis |
| ↑↑ WBC + ↑ Basophils + ↑ Thrombocytes | CML |
| ↑ WBC + ↑ Lymphocytes | CLL / Viral infection |
| ↓ WBC + ↓ Neutrophils | Viral infection / Agranulocytosis |
| ↑ Eosinophils | Allergy / Parasites |
| ↑ Monocytes + ↑ ESR | TB / Chronic infection |
| ↓ Platelets alone | ITP |
| ↑↑ ESR + ↑ WBC | Acute infection / Malignancy / Autoimmune |