Haem Practical rev 1

What is the function of a microhaematocrit centrifuge/reader?

It spins a capillary tube of blood at high speed to separate it into plasma, buffy coat, and packed red cells, allowing the PCV to be read directly.

What are the layers seen after centrifuging blood in a microhaematocrit tube?

Plasma, buffy coat, and packed red cells.

What does PCV stand for?

Packed Cell Volume (Haematocrit).

What are the uses of a microhaematocrit centrifuge?

Rapid determination of PCV/haematocrit, assessment of anaemia and polycythaemia, and monitoring response to transfusion.

What is PCV?

The proportion of the capillary tube occupied by packed red cells, expressed as a percentage.

What is the normal PCV range in adults?

Approximately 36–48%.

How is PCV reported?

Alongside haemoglobin and red blood cell count as part of the full blood count.

What does a low PCV indicate?

Anaemia.

What does a high PCV suggest?

Polycythaemia or dehydration (haemoconcentration).

What is the function of the Westergren apparatus?

It measures the erythrocyte sedimentation rate (ESR).

What does ESR indirectly measure?

The presence of inflammation in the body.

What conditions are commonly associated with an elevated ESR?

Infections, cancers, and autoimmune diseases.

What are the uses of ESR?

Detecting inflammatory conditions, screening for infection, autoimmune disease or malignancy, and monitoring disease activity and response to treatment.

Which bacterial infections commonly elevate ESR?

Bacterial infections generally elevate ESR.

Which autoimmune diseases commonly elevate ESR?

Rheumatoid arthritis and systemic lupus erythematosus (SLE).

Which malignancy classically causes a very high ESR?

Multiple myeloma.

Why does multiple myeloma markedly elevate ESR?

Due to increased serum globulins.

Besides inflammation, name two physiological conditions that elevate ESR.

Anaemia and pregnancy.

What does Perl's (Prussian blue) stain detect?

Stainable iron (haemosiderin).

What indicates a positive Perl's stain?

Blue granules within macrophages or erythroblasts.

What do blue granules in macrophages represent on Perl's stain?

Bone marrow iron stores.

What do blue granules in erythroblasts indicate?

Ring sideroblasts.

What are the uses of Perl's stain?

Assessing bone marrow iron stores, diagnosing iron deficiency versus sideroblastic anaemia/MDS, and assessing iron overload.

What finding on Perl's stain suggests iron deficiency?

Absent marrow iron stores.

What finding on Perl's stain suggests sideroblastic anaemia?

Presence of ring sideroblasts.

In which patients is Perl's stain useful for assessing iron overload?

Patients with thalassaemia and transfusion-dependent patients.

Which vacutainer tube contains no anticoagulant?

Red (plain) tube.

What is the main use of the red (plain) vacutainer tube?

Collection of serum for serology and biochemistry.

Which vacutainer tube contains sodium fluoride?

Grey tube.

What is the use of the grey vacutainer tube?

Glucose estimation.

Which anticoagulant is present in the purple vacutainer tube?

EDTA.

Which anticoagulant is present in the green vacutainer tube (haematology context)?

EDTA.

What are the uses of EDTA tubes?

Complete blood count, ESR, peripheral blood film, reticulocyte count, HbA1c, and blood film morphology.

Why is EDTA preferred for haematological investigations?

It chelates calcium, preventing clotting without distorting cell morphology.

Which vacutainer contains 3.2% sodium citrate?

Light blue tube.

What investigations use the light blue tube?

Coagulation studies such as PT and aPTT.

What is the correct blood-to-citrate ratio for coagulation studies?

9:1 blood to citrate.

How much citrate is mixed with 4.5 mL of blood?

0.5 mL citrate.

Which vacutainer contains heparin?

Green/black tube.

What is the use of the heparin tube?

Bone marrow studies.

Which vacutainer contains citrate for blood cultures?

Orange tube.

Which vacutainer is used for blood bank testing?

Pink (K₂EDTA) tube.

What blood bank tests are performed using the pink tube?

Blood grouping, ABO typing, and blood typing.

Which haematological investigations require EDTA?

FBC, peripheral blood film, ESR, reticulocyte count, HbA1c, and blood film morphology.

Which investigations require a plain (serum) bottle?

Serum protein electrophoresis, serum ferritin, serum iron, TIBC, serum vitamin B12, folate, LDH, and other serum-based tests.

Why is a plain bottle used instead of EDTA for ferritin estimation?

Ferritin is measured in serum, not plasma.

What machine performs a Full Blood Count automatically?

A Full Blood Count (FBC) autoanalyzer/automated haematology analyzer.

What are four parameters measured by an FBC autoanalyzer?

Haemoglobin, PCV, red blood cell count, and white blood cell count with differential.

What additional parameters can an FBC autoanalyzer measure?

Platelet count, MCV, MCH, MCHC, and RDW.

What are the uses of an FBC autoanalyzer?

Rapid screening for anaemia, infection, leukaemia, thrombocytopenia, providing red cell indices, and flagging abnormal cells for manual review.

Why are red cell indices useful?

They help classify anaemia into microcytic, normocytic, or macrocytic.

What abnormal findings may prompt a manual blood film review?

Abnormal cell populations flagged by the analyzer.

What components make up a Full Blood Count?

Haemoglobin, PCV, RBC count, WBC count with 5-part differential, platelet count, MCV, MCH, MCHC, and RDW.

What are the five white blood cell differentials in an FBC?

Neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

What is the function of an apheresis machine?

It separates whole blood into individual components and returns unwanted components to the donor or patient.

Which blood components can be separated by apheresis?

Packed red cells, fresh frozen plasma, platelet concentrate, cryoprecipitate, and granulocyte concentrate.

What is plasmapheresis?

Collection or exchange of plasma using an apheresis machine.

What is plateletpheresis?

Collection of platelets using an apheresis machine.

What is therapeutic plasma exchange?

Removal and replacement of plasma to treat certain diseases.

Name three diseases treated with therapeutic plasma exchange.

Thrombotic thrombocytopenic purpura (TTP), myasthenia gravis, and Guillain–Barré syndrome.

What is leukapheresis?

Rapid removal of white blood cells in patients with hyperleukocytosis.

Which leukaemias commonly require leukapheresis?

Chronic myeloid leukaemia (CML) and acute myeloid leukaemia (AML).

In which condition is platelet reduction by apheresis performed?

Essential thrombocythaemia.

What is the minimum age for blood donation?

18 years.

What is the maximum age for routine blood donation?

65 years.

What is the minimum acceptable body weight for blood donation?

50 kg.

What is the minimum haemoglobin level for female blood donors?

12.5 g/dL.

What is the minimum haemoglobin level for male blood donors?

13.0 g/dL.

Can a person with an active infection donate blood?

No.

Can a person with fever donate blood?

No.

Why are individuals with recent tattoos or piercings deferred from blood donation?

Due to the risk of transfusion-transmissible infections during the deferral period.

Can a pregnant woman donate blood?

No.

How long after delivery should a woman wait before donating blood?

At least 6 months.

Which transfusion-transmissible infections permanently exclude blood donation?

HIV, hepatitis B, hepatitis C, and syphilis.

Why is normal blood pressure required before blood donation?

To ensure donor safety during donation.

What is the minimum interval between blood donations?

At least 3 months.

Name all the major criteria for blood donation.

Age 18–65 years, weight ≥50 kg, Hb ≥12.5 g/dL (women) or ≥13.0 g/dL (men), no active infection or fever, no high-risk sexual behaviour, no recent tattoo/piercing, not pregnant or within 6 months postpartum, no transfusion-transmissible infection, normal blood pressure, and at least 3 months since the last donation.

What is the appearance of microcytic hypochromic red cells?

Small, pale red cells with an enlarged central pallor due to reduced haemoglobin content.

Which two diseases classically produce microcytic hypochromic red cells?

Iron deficiency anaemia and thalassaemia.

What is koilonychia?

Spoon-shaped, concave nails that are brittle and lose their lustre.

In which disease is koilonychia classically seen?

Iron deficiency anaemia.

What are the differential diagnoses of microcytic hypochromic anaemia?

Iron deficiency anaemia, thalassaemia, anaemia of chronic disease, sideroblastic anaemia, and lead poisoning.

What are the major causes of iron deficiency anaemia?

Increased demand, inadequate intake, malabsorption, and chronic blood loss.

Which physiological states increase iron demand?

Pregnancy, growth, and puberty.

Which gastrointestinal disease may cause iron deficiency by malabsorption?

Coeliac disease.

Which gastric condition can cause iron deficiency due to impaired absorption?

Achlorhydria.

Which gastrointestinal lesions commonly cause iron deficiency anaemia?

Bleeding gastrointestinal lesions.

Which intestinal parasite commonly causes iron deficiency anaemia?

Hookworm.

Which gynaecological condition commonly causes iron deficiency anaemia?

Menorrhagia.

Which medications may contribute to iron deficiency through chronic bleeding?

NSAIDs and anticoagulants.

What investigations are performed in iron deficiency anaemia?

FBC, red cell indices, peripheral blood film, serum iron, TIBC, serum ferritin, transferrin saturation, and bone marrow with Perl's stain if necessary.

How is serum iron affected in iron deficiency anaemia?

Decreased.

How is TIBC affected in iron deficiency anaemia?

Increased.

What is the most specific laboratory test for iron deficiency anaemia?

Low serum ferritin.

How is transferrin saturation affected in iron deficiency anaemia?

Decreased.

When is bone marrow examination with Perl's stain indicated in iron deficiency anaemia?

When the diagnosis remains uncertain.

What is the first principle in treating iron deficiency anaemia?

Treat the underlying cause.

How long should oral iron therapy be continued?

For 3–6 months and beyond normalization of haemoglobin to replenish iron stores.

Why is vitamin C recommended with oral iron therapy?

It enhances iron absorption.