Hematology Question Bank

 Two Marks Questions

What is Hematology?

Hematology is the study of blood.

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The area of medicine known as hematology studies blood, blood-forming organs, and blood disorders. It covers the study of blood cells, their roles, and illnesses associated with them.

What is Total Leukocyte Count (TLC)?
It is the quantity or number of  white blood cells in one cubic millimeter (mm³) of blood is known as the total leukocyte count. Adults have between 4,000 and 11,000 cells/mm³.

What is blood?

It is a specialized connective tissue fluid that travels or flows inside the body through blood vessels (i.e. arteries, veins, capillaries). The blood supply waste materials, nutrients, hormones, and oxygen throughout the body.

What are the main components of blood?

Blood consists of plasma and formed elements. The formed elements include red blood cells (RBCs), white blood cells (WBCs), and platelets.

What is Hemoglobinometry?
Hemoglobinometry is the measurement of hemoglobin concentration in blood. It is commonly used to diagnose anemia and assess oxygen-carrying capacity.

What are the normal hemoglobin values in adults?

The normal hemoglobin value in adult males is about 13–17 g/dL and in adult females about 12–15 g/dL. Values lower than normal may indicate anemia.

What is Differential Leukocyte Count (DLC)?
Differential Leukocyte Count measures the percentage distribution of different types of white blood cells in blood. It helps in diagnosing infections, allergies, and blood disorders.

What are the five types of white blood cells?
The five types of WBCs are neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Each type has a specific role in the immune response.

What is the function of red blood cells?
Red blood cells carry oxygen from the lungs to body tissues and transport carbon dioxide back to the lungs. This function is performed by hemoglobin present in RBCs.

What is the function of white blood cells?
White blood cells protect the body against infections and foreign substances. They are an essential part of the immune system.

What is the function of platelets?
Platelets help in blood clotting and prevent excessive bleeding when a blood vessel is injured. They form a platelet plug during clot formation.

What is Erythrocyte Sedimentation Rate (ESR)?
ESR is the rate at which red blood cells settle at the bottom of a vertical tube within one hour. It is used as a non-specific indicator of inflammation.

Name one method used for ESR estimation.
The Westergren method is commonly used to measure ESR. It is considered the standard method in many laboratories.

What does an increased ESR indicate?
An increased ESR usually indicates inflammation, infection, autoimmune disorders, or certain chronic diseases. It helps monitor disease progression.

What is Packed Cell Volume (PCV)?
Packed Cell Volume is the percentage of red blood cells present in the total blood volume. It is also called hematocrit.

What are the normal PCV values in adults?
The normal PCV value is about 40–54% in adult males and 36–48% in adult females. It helps in assessing anemia and dehydration.

What are Red Cell Indices?
Red cell indices are calculated values that describe the size and hemoglobin content of red blood cells. The main indices are MCV, MCH, and MCHC.

What does Mean Corpuscular Volume (MCV) indicate?
MCV indicates the average size or volume of red blood cells. It helps classify anemia as microcytic, normocytic, or macrocytic.

What does Mean Corpuscular Hemoglobin (MCH) represent?
MCH represents the average amount of hemoglobin present in a single red blood cell. It helps evaluate hemoglobin content of RBCs.

What does Mean Corpuscular Hemoglobin Concentration (MCHC) indicate?
MCHC indicates the average concentration of hemoglobin in red blood cells. It helps diagnose certain types of anemia.

What is Absolute Eosinophil Count (AEC)?
Absolute Eosinophil Count is the total number of eosinophils present per cubic millimeter of blood. It is useful in diagnosing allergic and parasitic conditions.

What is the normal range of Absolute Eosinophil Count?
The normal AEC range is about 40–400 cells/mm³. Increased levels may occur in allergies, asthma, or parasitic infections.

What is venipuncture?
Venipuncture is the procedure of collecting blood from a vein using a sterile needle and syringe or vacuum system. It is commonly performed for laboratory investigations.

Why is EDTA used as an anticoagulant in hematology?
EDTA prevents blood clotting by binding calcium ions. It preserves blood cell morphology and is widely used for hematological tests.

Why is proper mixing of blood with anticoagulant necessary?
Proper mixing prevents clot formation and ensures uniform distribution of cells. This helps obtain accurate laboratory results.

What is leukocytosis?
Leukocytosis refers to an increase in the total leukocyte count above the normal range. It usually occurs during infections or inflammatory conditions.

What is leukopenia?
Leukopenia is a decrease in the total leukocyte count below normal levels. It may occur due to viral infections, bone marrow disorders, or certain drugs.

What instrument is used for manual cell counting in hematology?
A Neubauer counting chamber (hemocytometer) is commonly used for manual counting of blood cells. It allows counting under a microscope.

What are formed elements of blood?
Formed elements are the cellular components of blood. They include red blood cells, white blood cells, and platelets.

What percentage of blood is plasma?
Plasma forms about 55% of total blood volume. It contains water, proteins, nutrients, hormones, and waste products.

What are the main functions of blood?
Blood transports oxygen, nutrients, and hormones to tissues. It also removes waste products and helps maintain body temperature and immunity.

Which white blood cell has the highest percentage in DLC?
Neutrophils usually have the highest percentage in differential leukocyte count. They play an important role in fighting bacterial infections.

What is the clinical significance of hemoglobin estimation?
Hemoglobin estimation helps diagnose anemia and polycythemia. It also evaluates the oxygen-carrying capacity of blood.

What is the importance of hematology in medical diagnosis?
Hematology helps detect many diseases such as anemia, infections, leukemia, and clotting disorders. It plays a vital role in laboratory medicine.

What error can occur due to hemolysis of blood sample?
Hemolysis causes destruction of red blood cells and release of hemoglobin into plasma. This can lead to inaccurate laboratory results.

Why is proper blood collection important in hematology tests?
Proper collection prevents contamination, clotting, and hemolysis. This ensures reliable and accurate laboratory findings.

What is the normal role of eosinophils in the body?
Eosinophils help in defense against parasitic infections and participate in allergic reactions. They are part of the immune system.

What does a high Absolute Eosinophil Count indicate?
An increased AEC may indicate allergic disorders, asthma, parasitic infections, or certain skin diseases. It helps clinicians in diagnosis.

What is the role of bone marrow in hematology?
Bone marrow is the primary site of blood cell formation. It produces red blood cells, white blood cells, and platelets.

Why are hematological investigations important before surgery?
They help assess the patient’s blood status such as hemoglobin level and clotting ability. This reduces the risk of bleeding or complications during surgery.

FOUR     MARKS   QUESTIONS

Question: Explain Hematology and describe its importance in medical science.

Answer:
Hematology is the branch of medical science that deals with the study of blood, blood-forming organs, and blood diseases. It includes the study of red blood cells, white blood cells, platelets, hemoglobin, and plasma. Hematology is important because many diseases can be diagnosed by examining blood. Conditions such as anemia, infections, leukemia, clotting disorders, and nutritional deficiencies can be detected through hematological investigations. Blood tests also help in monitoring treatment and evaluating the overall health status of patients. Therefore, hematology plays a vital role in diagnosis, treatment planning, and patient management in modern healthcare.

Question: Describe the composition of blood and its major functions in the human body.

Answer:
Blood is a specialized fluid connective tissue that circulates throughout the body. It consists of plasma and formed elements. Plasma forms about 55% of blood and contains water, proteins, nutrients, hormones, and waste products. The formed elements include red blood cells (RBCs), white blood cells (WBCs), and platelets. RBCs carry oxygen and carbon dioxide, WBCs help in body defense against infections, and platelets are involved in blood clotting. Blood performs several functions such as transportation of gases, nutrients, hormones, and waste products. It also helps regulate body temperature, maintain pH balance, and protect the body through immune responses and clot formation.

Question: Explain the procedure and importance of collection and preservation of blood samples for hematological investigations.

Answer:
Blood collection is an important step in hematological investigations. Blood is usually collected by venipuncture using sterile syringes or vacuum tubes. The most commonly used anticoagulant for hematology tests is EDTA, which prevents clotting and preserves cell morphology. Proper labeling, gentle mixing with anticoagulant, and avoiding hemolysis are essential for accurate results. The sample should be analyzed as soon as possible or stored at recommended temperatures if there is a delay. Incorrect collection, contamination, or improper storage may lead to false results. Proper sample collection and preservation ensure reliability and accuracy in hematological investigations.

Question: Define Haemoglobinometry and explain its normal values and clinical significance.

Answer:
Haemoglobinometry is the laboratory estimation of the concentration of hemoglobin present in blood. Hemoglobin is a protein in red blood cells responsible for transporting oxygen from the lungs to body tissues. The normal hemoglobin value in adult males is approximately 13–17 g/dL and in adult females is about 12–15 g/dL. Estimation of hemoglobin helps in diagnosing conditions such as anemia, polycythemia, and blood loss. Low hemoglobin levels indicate anemia, nutritional deficiencies, or chronic diseases, while high levels may occur in dehydration or polycythemia. Accurate haemoglobin estimation is essential for assessing oxygen-carrying capacity and overall health.

Question: Define Total Leucocyte Count (TLC) and mention its normal value and clinical significance.

Answer:
Total Leucocyte Count (TLC) is the measurement of the total number of white blood cells present in one cubic millimeter (mm³) or microliter of blood. White blood cells play a vital role in protecting the body against infections and foreign substances. The normal TLC range in adults is approximately 4,000 to 11,000 cells per microliter of blood. An increased TLC, known as leukocytosis, may occur in infections, inflammation, leukemia, or stress. A decreased TLC, called leukopenia, may occur in viral infections, bone marrow disorders, or certain drug therapies. TLC is an important test for evaluating immune function and diagnosing many diseases.

Question: What is Differential Leucocyte Count (DLC)? Explain its normal values and significance.

Answer:
Differential Leucocyte Count (DLC) refers to the percentage distribution of different types of white blood cells in the blood. It includes neutrophils, lymphocytes, monocytes, eosinophils, and basophils. The normal values are approximately: neutrophils 40–70%, lymphocytes 20–40%, monocytes 2–8%, eosinophils 1–6%, and basophils less than 1%. DLC helps in identifying the type of infection or disease affecting the patient. For example, increased neutrophils suggest bacterial infections, increased lymphocytes may indicate viral infections, and increased eosinophils are commonly seen in allergies and parasitic infections. Thus, DLC provides valuable information for clinical diagnosis.

Define collection of blood via venipuncture

Venipuncture is the procedure of obtaining blood from a vein using a sterile needle and syringe or vacutainer system for laboratory investigations, especially for haematological, biochemical, and serological tests.

Procedure for Collection of Blood via Venipuncture:

1. Preparation of Materials
   Assemble all necessary materials such as syringe or vacutainer, sterile needle, tourniquet, alcohol swab, cotton, gloves, and anticoagulant tube (e.g., EDTA tube).

2. Patient Identification and Positioning
   Confirm the patient’s identity and make the patient sit or lie comfortably with the arm extended.

3. Application of Tourniquet and Vein Selection
   Apply a tourniquet about 3–4 cm above the puncture site and select a suitable vein, commonly the Median Cubital Vein in the antecubital fossa.

4. Cleaning of Puncture Site
   Clean the area with an alcohol swab and allow it to dry to maintain aseptic conditions.

5. Insertion of Needle
   Insert the sterile needle into the vein at an angle of 15–30° with the bevel facing upward.

6. Collection of Blood
   Withdraw the required amount of blood using a syringe or allow blood to flow into the vacutainer tube.

7. Release of Tourniquet and Needle Removal
   Release the tourniquet once blood flow is established, then remove the needle and apply gentle pressure with sterile cotton.

8. Transfer and Mixing of Blood
   Transfer the blood into an anticoagulant tube containing Ethylenediaminetetraacetic acid (EDTA) and mix gently to prevent clotting.

9. Labeling and Transport
   Label the sample properly with patient details and send it to the laboratory for analysis.

Question: Define Erythrocyte Sedimentation Rate (ESR) and explain its normal values and clinical importance.

Answer:
Erythrocyte Sedimentation Rate (ESR) is the rate at which red blood cells settle at the bottom of a vertical tube of anticoagulated blood within one hour. It is usually measured using the Westergren method. The normal ESR value for adult males is about 0–15 mm per hour and for adult females is 0–20 mm per hour. ESR is a non-specific test that indicates the presence of inflammation in the body. Increased ESR may occur in infections, tuberculosis, autoimmune diseases, anemia, and cancers. Although it does not diagnose a specific disease, ESR helps in detecting and monitoring inflammatory conditions.

Question: Explain Red Cell Indices (RCI) and their importance in diagnosing anemia.

Answer:
Red Cell Indices (RCI) are calculated values that describe the size and hemoglobin content of red blood cells. The main indices include Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH), and Mean Corpuscular Hemoglobin Concentration (MCHC). These indices help classify different types of anemia. For example, low MCV indicates microcytic anemia, while high MCV indicates macrocytic anemia. MCH reflects the amount of hemoglobin in each red cell, and MCHC indicates the concentration of hemoglobin within red cells. Red cell indices are important diagnostic tools that help clinicians determine the cause and type of anemia for proper treatment.

Difference between Plasma and Serum

Feature	Plasma	Serum
Definition	Plasma is the liquid portion of blood obtained when blood is collected with anticoagulant and then centrifuged.	Serum is the liquid portion of blood after clotting when blood is allowed to clot and then centrifuged.
Clotting factors	Contains clotting factors such as Fibrinogen, prothrombin, etc.	Does not contain fibrinogen because it is used up during clot formation.
Method of collection	Blood is collected in tubes containing anticoagulants (e.g., EDTA, heparin, citrate) and centrifuged.	Blood is collected without anticoagulant, allowed to clot, and then centrifuged.
Appearance	Slightly yellowish liquid above the blood cells after centrifugation.	Also a clear yellowish fluid, but slightly clearer than plasma.
Uses in laboratory	Used for coagulation studies and some biochemical tests.	Commonly used for biochemical tests, serology, and immunology tests.

NOTE:

• Plasma = Liquid part of anticoagulated blood (contains clotting factors).

• Serum = Liquid part of clotted blood (lacks fibrinogen).

EIGHT MARKS QUESTIONS

Define Hemoglobinometry. Mention its normal values, clinical significance, and possible errors involved in the test.

Hemoglobinometry is the laboratory measurement of the concentration of hemoglobin present in the blood. Hemoglobin is an iron-containing protein found in red blood cells that is responsible for transporting oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs.

The estimation of hemoglobin is an important routine hematological test used to assess the oxygen-carrying capacity of blood. It is commonly performed using methods such as Sahli’s method or the cyanmethemoglobin method.

The normal hemoglobin values vary according to age and sex. In adult males, the normal range is approximately 13–18 g/dL, while in adult females it is about 12–16 g/dL. In children, the normal values are slightly lower depending on age.

The clinical significance of hemoglobin estimation is very important in diagnosing various medical conditions. A decreased hemoglobin level indicates anemia, which may occur due to nutritional deficiencies (iron, vitamin B12, or folic acid), blood loss, chronic diseases, or bone marrow disorders. Increased hemoglobin levels may be seen in conditions such as polycythemia, dehydration, or living at high altitudes.

Several errors can occur during hemoglobin estimation that may affect the accuracy of results. These include improper blood collection, insufficient mixing of blood with anticoagulant, incorrect dilution, use of dirty glassware, and faulty calibration of instruments. In Sahli’s method, subjective color comparison may also lead to reading errors.

Proper technique, accurate measurement, and well-maintained equipment are necessary to obtain reliable hemoglobin values in hematological investigations.

Describe the procedure for collection and preservation of blood samples for hematological investigations.

The collection and preservation of blood samples are essential steps in hematological investigations because accurate laboratory results depend greatly on proper sampling techniques.

Blood samples for hematological tests are usually collected by venipuncture. The procedure begins with proper identification of the patient and preparation of the required materials such as sterile syringe or vacutainer, needles, antiseptic swabs, gloves, and collection tubes containing anticoagulants.

First, the phlebotomist selects a suitable vein, usually the median cubital vein located in the antecubital fossa of the arm. A tourniquet is applied above the site to make the vein more prominent. The area is cleaned with an antiseptic solution such as alcohol to prevent infection.

A sterile needle is then inserted into the vein and the required amount of blood is withdrawn using a syringe or vacutainer system. After the blood is collected, the tourniquet is released and the needle is carefully removed. Pressure is applied to the puncture site using sterile cotton to stop bleeding.

The collected blood is transferred into appropriate tubes depending on the test required. For most hematological tests, ethylenediaminetetraacetic acid (EDTA) is used as an anticoagulant because it prevents clotting and preserves cellular morphology.

Proper preservation of the sample is important to maintain the integrity of blood cells. The sample should be gently mixed with the anticoagulant to prevent clot formation. It should be labeled correctly with the patient’s details, date, and time of collection.

If testing is not performed immediately, the sample should be stored at an appropriate temperature, usually 2–8°C, and analyzed within the recommended time to avoid deterioration of blood cells and inaccurate results.

Explain the composition of blood, its functions, and the normal cellular components of blood.

Blood is a specialized fluid connective tissue that circulates throughout the body through blood vessels. It performs several vital functions necessary for maintaining life. Blood consists of two main components: plasma and formed elements.

Plasma constitutes about 55% of the total blood volume and is a pale yellow fluid mainly composed of water (about 90–92%). It also contains proteins such as albumin, globulins, and fibrinogen, along with electrolytes, nutrients, hormones, enzymes, dissolved gases, and waste products. Plasma helps in maintaining osmotic balance, transporting substances, and supporting clotting mechanisms.

The formed elements make up about 45% of the blood and include red blood cells (RBCs), white blood cells (WBCs), and platelets.

Red blood cells, also called erythrocytes, are the most numerous cells in the blood. They contain haemoglobin, which is responsible for transporting oxygen from the lungs to body tissues and carrying carbon dioxide back to the lungs. The normal RBC count in adults is approximately 4.5–5.5 million cells per microliter in males and 4–5 million cells per microliter in females.

White blood cells, or leucocytes, play an essential role in the immune system and help protect the body against infections. The normal WBC count ranges from 4,000 to 11,000 cells per microliter. There are five types of WBCs: neutrophils, lymphocytes, monocytes, eosinophils, and basophils.

Platelets, also known as thrombocytes, are small cell fragments involved in blood clotting. Their normal count ranges between 150,000 and 400,000 per microliter of blood.

Blood performs several important functions including transportation of oxygen, nutrients, hormones, and waste products, regulation of body temperature and pH, and protection through immune responses and blood clotting.

Explain Erythrocyte Sedimentation Rate (ESR). Mention its normal values, clinical significance, and errors involved in the test.

Erythrocyte Sedimentation Rate (ESR) is a laboratory test that measures the rate at which red blood cells settle at the bottom of a vertical tube over a specified period, usually one hour. It is a simple and non-specific test used to detect inflammation and monitor disease activity.

The test is commonly performed using the Westergren method, which is considered the standard method. In this method, anticoagulated blood is placed in a vertical Westergren tube, and the distance that the red blood cells fall in one hour is measured in millimeters.

Normal ESR values vary depending on age and sex. In adult males, the normal ESR is usually 0–15 mm per hour, while in adult females it is approximately 0–20 mm per hour. In children, the values are generally lower.

The clinical significance of ESR lies in its ability to indicate the presence of inflammation in the body. An increased ESR may be observed in infections, inflammatory diseases, tuberculosis, rheumatoid arthritis, anemia, and certain malignancies. It is also used to monitor the progression or response to treatment in chronic diseases.

However, ESR is a non-specific test and cannot diagnose a particular disease by itself. It should always be interpreted along with other clinical findings and laboratory tests.

Several factors can lead to errors in ESR measurement. These include improper mixing of blood with anticoagulant, incorrect positioning of the tube, vibration during the test, delayed testing after sample collection, and incorrect anticoagulant ratio. Temperature variations and tilted tubes may also affect the sedimentation rate.

Define Total Leucocyte Count (TLC) and Differential Leucocyte Count (DLC). Mention their normal values and clinical significance.

Total Leucocyte Count (TLC) is the measurement of the total number of white blood cells present in a specific volume of blood, usually expressed as cells per microliter. Differential Leucocyte Count (DLC) refers to the percentage distribution of the different types of white blood cells present in the blood.

The TLC provides an overall measure of the body’s immune status. The normal total leucocyte count in adults ranges from 4,000 to 11,000 cells per microliter of blood.

The Differential Leucocyte Count identifies the proportion of each type of white blood cell. The normal values are approximately: neutrophils 40–70%, lymphocytes 20–40%, monocytes 2–8%, eosinophils 1–6%, and basophils less than 1%.

The clinical significance of TLC and DLC is very important in diagnosing and monitoring many diseases. An increased total leucocyte count, known as leucocytosis, may occur in bacterial infections, inflammation, leukemia, and tissue injury. A decreased leucocyte count, known as leucopenia, may occur in viral infections, bone marrow disorders, or as a result of certain medications.

The differential count helps identify which type of white blood cell is increased or decreased. For example, neutrophilia is commonly seen in bacterial infections, lymphocytosis in viral infections, eosinophilia in allergic reactions and parasitic infections, and monocytosis in chronic infections.

Errors in these tests can occur due to improper blood sample collection, clotting of blood, inadequate mixing with anticoagulant, incorrect dilution during manual counting, or poor preparation of blood smear for DLC examination.

Accurate laboratory techniques and careful microscopic examination are essential for obtaining reliable TLC and DLC results in hematological investigations.

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