MBBS Year
1st Year
Subject
What Is Usually Asked
Erythropoiesis, haemoglobin, red cell indices
ReferenceAll Years (1st-Final)All UniversitiesAnaemia
Anaemia: Notes, PPT and PYQs for MBBS
Anaemia is a reduction in haemoglobin concentration, red cell count or haematocrit below the normal level for a person's age, sex and physiological state, which reduces the oxygen-carrying capacity of blood. It appears in almost every year of MBBS: Physiology and Biochemistry in 1st Year, Pathology and Pharmacology in 2nd Year, Community Medicine in 3rd Year, and Medicine, Obstetrics and Paediatrics in Final Year.
SME-reviewed. Updated 2026.
Open in GeckoMed for PPT slides and offline notesQuick Summary: What You Need to Know for University Exams
- Anaemia is classified morphologically (microcytic, normocytic, macrocytic) and aetiologically (reduced production, increased destruction, blood loss).
- Iron deficiency anaemia is the most common type worldwide and in India.
- Serum ferritin is the most useful single test for iron deficiency; a low ferritin confirms low iron stores.
- Megaloblastic anaemia is due to vitamin B12 or folate deficiency; B12 deficiency can also cause neurological damage.
- Haemolytic anaemias show raised indirect bilirubin, raised LDH, low haptoglobin and reticulocytosis.
- Treatment targets the underlying cause, not just the haemoglobin level.
- India's Anaemia Mukt Bharat strategy targets six population groups.
Anaemia Across MBBS Subjects
| MBBS Year | Subject | What Is Usually Asked |
|---|---|---|
| 1st Year | Physiology | Erythropoiesis, haemoglobin, red cell indices |
| 1st Year | Biochemistry | Iron metabolism, haem synthesis, vitamin B12 and folate |
| 2nd Year | Pathology | Classification, iron deficiency, megaloblastic and haemolytic anaemias, blood smear |
| 2nd Year | Pharmacology | Oral and parenteral iron, vitamin B12, folic acid, erythropoietin |
| 3rd Year | Community Medicine | Nutritional anaemia, Anaemia Mukt Bharat |
| Final Year | General Medicine | Approach to anaemia, evaluation, management |
| Final Year | Obstetrics and Gynaecology | Anaemia in pregnancy |
| Final Year | Paediatrics | Nutritional anaemia, thalassaemia |
MBBS Year
1st Year
Subject
What Is Usually Asked
Iron metabolism, haem synthesis, vitamin B12 and folate
MBBS Year
2nd Year
Subject
What Is Usually Asked
Classification, iron deficiency, megaloblastic and haemolytic anaemias, blood smear
MBBS Year
2nd Year
Subject
What Is Usually Asked
Oral and parenteral iron, vitamin B12, folic acid, erythropoietin
MBBS Year
3rd Year
Subject
What Is Usually Asked
Nutritional anaemia, Anaemia Mukt Bharat
MBBS Year
Final Year
Subject
What Is Usually Asked
Approach to anaemia, evaluation, management
MBBS Year
Final Year
Subject
What Is Usually Asked
Anaemia in pregnancy
MBBS Year
Final Year
Subject
What Is Usually Asked
Nutritional anaemia, thalassaemia
Definition and Classification
WHO Haemoglobin Cut-Offs (Classic Values)
| Group | Anaemia If Haemoglobin Is Below |
|---|---|
| Adult men | 13 g/dL |
| Non-pregnant women | 12 g/dL |
| Pregnant women | 11 g/dL (WHO's 2024 guideline adds trimester-specific values) |
| Children 6 to 59 months | 11 g/dL |
Group
Adult men
Anaemia If Haemoglobin Is Below
13 g/dL
Group
Non-pregnant women
Anaemia If Haemoglobin Is Below
12 g/dL
Group
Pregnant women
Anaemia If Haemoglobin Is Below
11 g/dL (WHO's 2024 guideline adds trimester-specific values)
Group
Children 6 to 59 months
Anaemia If Haemoglobin Is Below
11 g/dL
Severity of Anaemia (WHO, Adults)
| Severity | Men (g/dL) | Non-Pregnant Women (g/dL) |
|---|---|---|
| Mild | 11 to 12.9 | 11 to 11.9 |
| Moderate | 8 to 10.9 | 8 to 10.9 |
| Severe | Below 8 | Below 8 |
Severity
Mild
Men (g/dL)
11 to 12.9
Non-Pregnant Women (g/dL)
11 to 11.9
Severity
Moderate
Men (g/dL)
8 to 10.9
Non-Pregnant Women (g/dL)
8 to 10.9
Severity
Severe
Men (g/dL)
Below 8
Non-Pregnant Women (g/dL)
Below 8
Morphological Classification (Based on Red Cell Indices)
| Type | MCV | Common Causes |
|---|---|---|
| Microcytic hypochromic | Low | Iron deficiency, thalassaemia, anaemia of chronic disease (some cases), sideroblastic anaemia |
| Normocytic normochromic | Normal | Acute blood loss, haemolysis, aplastic anaemia, chronic kidney disease, anaemia of chronic disease |
| Macrocytic | High | Megaloblastic (vitamin B12 or folate deficiency); non-megaloblastic (liver disease, alcohol, hypothyroidism, reticulocytosis) |
Type
Microcytic hypochromic
MCV
Low
Common Causes
Iron deficiency, thalassaemia, anaemia of chronic disease (some cases), sideroblastic anaemia
Type
Normocytic normochromic
MCV
Normal
Common Causes
Acute blood loss, haemolysis, aplastic anaemia, chronic kidney disease, anaemia of chronic disease
Type
Macrocytic
MCV
High
Common Causes
Megaloblastic (vitamin B12 or folate deficiency); non-megaloblastic (liver disease, alcohol, hypothyroidism, reticulocytosis)
Aetiological Classification
- Reduced red cell production: Nutritional deficiency (iron, vitamin B12, folate), bone marrow failure (aplastic anaemia), marrow infiltration, chronic kidney disease, anaemia of chronic disease
- Increased red cell destruction (haemolysis):
- Inherited: hereditary spherocytosis, G6PD deficiency, sickle cell disease, thalassaemia
- Acquired: autoimmune haemolytic anaemia, malaria, drugs, mechanical haemolysis
- Blood loss: Acute (trauma, haemorrhage) or chronic (menorrhagia, hookworm infestation, gastrointestinal bleeding)
Aetiology of Iron Deficiency Anaemia (Most Common Type)
| Cause | Examples |
|---|---|
| Inadequate intake | Diet low in iron or poor bioavailability |
| Increased requirement | Pregnancy, infancy, adolescence |
| Impaired absorption | Coeliac disease, gastrectomy |
| Chronic blood loss | Menorrhagia, hookworm infestation, peptic ulcer, colorectal cancer, haemorrhoids |
Cause
Inadequate intake
Examples
Diet low in iron or poor bioavailability
Cause
Increased requirement
Examples
Pregnancy, infancy, adolescence
Cause
Impaired absorption
Examples
Coeliac disease, gastrectomy
Cause
Chronic blood loss
Examples
Menorrhagia, hookworm infestation, peptic ulcer, colorectal cancer, haemorrhoids
Pathophysiology
Iron Deficiency: Stages
- Iron depletion: Stores fall (low ferritin), haemoglobin still normal
- Iron-deficient erythropoiesis: Serum iron and transferrin saturation fall, TIBC rises
- Iron deficiency anaemia: Haemoglobin falls, cells become microcytic and hypochromic
Megaloblastic Anaemia: Mechanism
- Deficiency of vitamin B12 or folate
- Impaired DNA synthesis in dividing cells
- Nuclear maturation lags behind cytoplasmic maturation (nuclear-cytoplasmic asynchrony)
- Large megaloblasts form in the marrow; many die in the marrow (ineffective erythropoiesis)
- Macrocytic anaemia, often with low white cell and platelet counts
Compensatory Mechanisms in Anaemia
- Increased cardiac output and heart rate
- Increased 2,3-BPG in red cells, shifting the oxygen dissociation curve to the right
- Redistribution of blood flow to vital organs
- Increased erythropoietin production
(Examiner may ask you to draw the iron metabolism or erythropoiesis diagram.)
Clinical Features
General Features of Anaemia
- Fatigue, weakness and reduced exercise tolerance
- Breathlessness on exertion and palpitations
- Pallor of the conjunctiva, palms, nail beds and tongue
- Tachycardia and a flow murmur
- Heart failure in severe anaemia
Features Pointing to a Specific Type
| Type | Specific Features |
|---|---|
| Iron deficiency | Koilonychia, angular stomatitis, glossitis, pica, Plummer-Vinson syndrome (dysphagia with oesophageal web) |
| Vitamin B12 deficiency | Glossitis, peripheral neuropathy, subacute combined degeneration of the spinal cord, cognitive changes |
| Folate deficiency | Glossitis; no neurological features |
| Haemolytic | Jaundice, splenomegaly, pigment gallstones, dark urine in intravascular haemolysis |
| Thalassaemia major | Growth failure, hepatosplenomegaly, bone changes such as frontal bossing |
Type
Iron deficiency
Specific Features
Koilonychia, angular stomatitis, glossitis, pica, Plummer-Vinson syndrome (dysphagia with oesophageal web)
Type
Vitamin B12 deficiency
Specific Features
Glossitis, peripheral neuropathy, subacute combined degeneration of the spinal cord, cognitive changes
Type
Folate deficiency
Specific Features
Glossitis; no neurological features
Type
Haemolytic
Specific Features
Jaundice, splenomegaly, pigment gallstones, dark urine in intravascular haemolysis
Type
Thalassaemia major
Specific Features
Growth failure, hepatosplenomegaly, bone changes such as frontal bossing
Diagnosis
Step-by-Step Approach
- Confirm anaemia with haemoglobin
- Classify by MCV
- Check the reticulocyte count (high suggests haemolysis or blood loss; low suggests reduced production)
- Examine the peripheral smear
- Do specific tests based on the likely type
Iron Studies: Key Differentiating Table
| Test | Iron Deficiency | Anaemia of Chronic Disease | Thalassaemia Trait |
|---|---|---|---|
| Serum iron | Low | Low | Normal |
| TIBC | High | Low or normal | Normal |
| Transferrin saturation | Low | Low or normal | Normal |
| Serum ferritin | Low | Normal or high | Normal |
| HbA2 (on electrophoresis) | Normal | Normal | Raised in beta-thalassaemia trait |
Test
Serum iron
Iron Deficiency
Low
Anaemia of Chronic Disease
Low
Thalassaemia Trait
Normal
Test
TIBC
Iron Deficiency
High
Anaemia of Chronic Disease
Low or normal
Thalassaemia Trait
Normal
Test
Transferrin saturation
Iron Deficiency
Low
Anaemia of Chronic Disease
Low or normal
Thalassaemia Trait
Normal
Test
Serum ferritin
Iron Deficiency
Low
Anaemia of Chronic Disease
Normal or high
Thalassaemia Trait
Normal
Test
HbA2 (on electrophoresis)
Iron Deficiency
Normal
Anaemia of Chronic Disease
Normal
Thalassaemia Trait
Raised in beta-thalassaemia trait
Mentzer index (MCV ÷ RBC count): a value above 13 favours iron deficiency, and below 13 favours thalassaemia trait.
Other Key Tests
| Test | Findings |
|---|---|
| Peripheral smear, iron deficiency | Microcytic hypochromic cells, pencil cells, raised RDW |
| Peripheral smear, megaloblastic | Macro-ovalocytes, hypersegmented neutrophils (five or more lobes) |
| Serum vitamin B12 and red cell folate | Confirm the deficiency |
| Haemolysis screen | Raised indirect bilirubin and LDH, low haptoglobin, reticulocytosis |
| Direct Coombs test | Positive in autoimmune haemolytic anaemia |
| Haemoglobin electrophoresis or HPLC | Thalassaemia and sickle cell disease |
| Bone marrow examination | Aplastic anaemia, marrow infiltration, unexplained cytopenias |
| Stool examination | Occult blood, hookworm ova |
Test
Peripheral smear, iron deficiency
Findings
Microcytic hypochromic cells, pencil cells, raised RDW
Test
Peripheral smear, megaloblastic
Findings
Macro-ovalocytes, hypersegmented neutrophils (five or more lobes)
Test
Serum vitamin B12 and red cell folate
Findings
Confirm the deficiency
Test
Haemolysis screen
Findings
Raised indirect bilirubin and LDH, low haptoglobin, reticulocytosis
Test
Direct Coombs test
Findings
Positive in autoimmune haemolytic anaemia
Test
Haemoglobin electrophoresis or HPLC
Findings
Thalassaemia and sickle cell disease
Test
Bone marrow examination
Findings
Aplastic anaemia, marrow infiltration, unexplained cytopenias
Test
Stool examination
Findings
Occult blood, hookworm ova
For reference ranges, see the blood test normal values chart for India.
Management
General Principles
- Identify and treat the underlying cause
- Replace the deficient nutrient
- Transfuse only when anaemia is severe, symptomatic or causing heart failure
- Monitor the response with haemoglobin and reticulocyte count
Treatment by Type
| Type | Treatment |
|---|---|
| Iron deficiency | Oral iron (for example ferrous sulphate) as first line; parenteral iron (iron sucrose, ferric carboxymaltose) if oral iron is not tolerated, not absorbed, or a rapid rise is needed. Continue iron for about three months after haemoglobin normalises to refill stores. Treat the cause, such as deworming for hookworm |
| Vitamin B12 deficiency | Parenteral vitamin B12 (cyanocobalamin or hydroxocobalamin); lifelong in pernicious anaemia |
| Folate deficiency | Oral folic acid. Do not give folic acid alone when B12 deficiency is present, because it can worsen neurological damage |
| Autoimmune haemolytic anaemia | Corticosteroids as first line; further immunosuppression or splenectomy in selected cases |
| Hereditary spherocytosis | Splenectomy in selected patients |
| Thalassaemia major | Regular transfusions with iron chelation; bone marrow transplantation where possible |
| Aplastic anaemia | Supportive care, immunosuppression, bone marrow transplantation |
| Chronic kidney disease | Erythropoiesis-stimulating agents with iron |
Type
Iron deficiency
Treatment
Oral iron (for example ferrous sulphate) as first line; parenteral iron (iron sucrose, ferric carboxymaltose) if oral iron is not tolerated, not absorbed, or a rapid rise is needed. Continue iron for about three months after haemoglobin normalises to refill stores. Treat the cause, such as deworming for hookworm
Type
Vitamin B12 deficiency
Treatment
Parenteral vitamin B12 (cyanocobalamin or hydroxocobalamin); lifelong in pernicious anaemia
Type
Folate deficiency
Treatment
Oral folic acid. Do not give folic acid alone when B12 deficiency is present, because it can worsen neurological damage
Type
Autoimmune haemolytic anaemia
Treatment
Corticosteroids as first line; further immunosuppression or splenectomy in selected cases
Type
Hereditary spherocytosis
Treatment
Splenectomy in selected patients
Type
Thalassaemia major
Treatment
Regular transfusions with iron chelation; bone marrow transplantation where possible
Type
Aplastic anaemia
Treatment
Supportive care, immunosuppression, bone marrow transplantation
Type
Chronic kidney disease
Treatment
Erythropoiesis-stimulating agents with iron
Response to iron therapy: The reticulocyte count rises first, followed by a steady rise in haemoglobin over the following weeks.
Complications
- High-output heart failure
- Angina in people with coronary artery disease
- Increased maternal and perinatal risks in pregnancy, including preterm birth and low birth weight
- Impaired growth and cognitive development in children
- Reduced work capacity
- Iron overload with repeated transfusions
- Neurological damage in untreated vitamin B12 deficiency
Prevention and Control (Community Medicine Angle)
Burden: According to the National Family Health Survey 2019-21 (NFHS-5), 67.1% of children aged 6 to 59 months and 57.0% of women aged 15 to 49 years in India were anaemic.
Anaemia Mukt Bharat: Launched in 2018 with a 6×6×6 strategy of six target groups, six interventions and six institutional mechanisms.
Six target groups:
- Children 6 to 59 months
- Children 5 to 9 years
- Adolescents 10 to 19 years
- Pregnant women
- Lactating mothers
- Women of reproductive age
Six interventions:
- Prophylactic iron and folic acid supplementation
- Periodic deworming
- Intensified behaviour change communication
- Testing and treatment of anaemia
- Provision of iron and folic acid fortified foods in government programmes
- Addressing non-nutritional causes of anaemia, such as malaria and haemoglobinopathies
Prognosis
Nutritional anaemias respond well to replacement once the cause is treated. Prognosis in haemolytic and aplastic anaemias depends on the underlying disease and access to specialised care.
Quick Viva Questions
Q: What is the earliest laboratory change in iron deficiency? A: A fall in serum ferritin, reflecting depleted iron stores.
Q: What is the earliest sign of response to iron therapy? A: A rise in the reticulocyte count, usually within about a week.
Q: What is koilonychia? A: Spoon-shaped nails, seen in long-standing iron deficiency.
Q: What are hypersegmented neutrophils? A: Neutrophils with five or more nuclear lobes, a feature of megaloblastic anaemia.
Q: Why is folic acid alone avoided in vitamin B12 deficiency? A: It can correct the anaemia while neurological damage continues to progress.
How Anaemia Appears in MBBS University Exams
Typical question styles (not attributed to specific papers or years):
- "Classify anaemia. Discuss the aetiology, clinical features, laboratory diagnosis and treatment of iron deficiency anaemia." (Long essay, Medicine or Pathology)
- "Describe the aetiopathogenesis and laboratory diagnosis of megaloblastic anaemia." (Long essay, Pathology)
- "Write a short note on laboratory findings in haemolytic anaemia." (Short note, Pathology)
- "Write a short note on parenteral iron preparations." (Short note, Pharmacology)
- "Write a short note on Anaemia Mukt Bharat." (Short note, Community Medicine)
- "Discuss the management of anaemia in pregnancy." (Obstetrics)
Frequently Asked Questions
What is the most common type of anaemia in India?
Iron deficiency anaemia is the most common type, driven by low dietary iron, increased needs in pregnancy and growth, and blood loss from causes such as hookworm infestation and menorrhagia.
Which is the best test to diagnose iron deficiency?
Serum ferritin is the most useful single test. A low ferritin confirms depleted iron stores, although ferritin can be falsely normal during inflammation.
Can I download the anaemia PPT for my presentation?
Yes. Use the Download PPT button at the top of this page. The GeckoMed app also gives offline access to the slides and notes.
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