Introduction to Hematology

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Questions and Answers

What is the primary purpose of using K2 or K3 EDTA as an anticoagulant?

To increase the lifespan of blood samples during testing

To prevent clotting of the blood specimen (correct)

To reduce the pH of the blood sample for better accuracy

To enhance the visibility of blood components under a microscope

What effect does aging have on the RBC count in EDTA samples?

It increases due to clumping of cells

It remains unchanged regardless of the age of the sample

It accurately reflects the RBC count at the time of collection

It becomes falsely low due to RBC lysis and fragments (correct)

What change is noted in aged EDTA samples regarding Hemoglobin (HGB) measurements?

HGB measures falsely high due to cell sedimentation

HGB measurement is accurate if RBCs are completely lysed (correct)

HGB measurements are completely unaffected by sample age

HGB levels become inconsistent and unreliable

Which change occurs in aged EDTA samples affecting Mean Corpuscular Volume (MCV)?

MCV is falsely low or high depending on the hemolysis level Signup and view all the answers

What type of RBC change is associated with spherocytes?

They indicate a fragile structure of RBCs Signup and view all the answers

Which parameter becomes falsely low when there is hemolysis in the sample?

Hematocrit (HCT) Signup and view all the answers

What should be avoided when preparing a blood sample for testing?

Formation of clots in the sample Signup and view all the answers

What impact does cold storage at 4°C have on blood samples?

It may induce cold agglutination affecting the sample Signup and view all the answers

What is the primary role of erythrocytes in the blood?

To transport oxygen to tissues Signup and view all the answers

Which plasma constituent makes up the largest percentage of plasma volume?

Water Signup and view all the answers

What is the function of platelets in the blood?

Plug capillaries and form clots Signup and view all the answers

What is hemostasis?

Arrest of bleeding Signup and view all the answers

What are leukocytes primarily responsible for?

Immune defense Signup and view all the answers

What does a Complete Blood Count (CBC) typically assess?

Quantification of various blood components Signup and view all the answers

What is the primary location for hematopoiesis in adults?

Bone marrow Signup and view all the answers

Which of the following components is NOT found in serum?

Fibrinogen Signup and view all the answers

Which function is NOT associated with plasma?

Fighting infections Signup and view all the answers

How does plasma differ from serum?

Plasma contains fibrinogen, serum does not Signup and view all the answers

Study Notes

Hematology Introduction

Hematology is the study of formed cellular blood elements, including white blood cells, red blood cells, and platelets.
Hemostasis is the process of stopping bleeding by forming a barrier to blood loss, maintaining an adequate number of cells to perform their functions.
Hematopoiesis is the dynamic formation and development of blood cells, primarily in the bone marrow, responsible for replacing circulating blood cells.

Functions of the Hematology Lab

Confirm a physician's clinical impression of a possible hematological disorder.
Establish a diagnosis or rule out a diagnosis.
Detect an unsuspected disorder.
Monitor the effects of radiation or chemotherapy.

Blood Composition

Plasma (55%):
- Primarily water (92%).
- Solutes (8%):
  - Albumins
  - Globulins
  - Fibrinogen
  - Electrolytes, hormones, vitamins, lipids, salts, enzymes, and carbohydrates.
Functions of Plasma:
- Transport medium for nutrients and metabolites.
- Immune defense.
- Coagulation.
Cellular Elements (1%):
- Leukocytes (White Blood Cells):
  - Granulocytes: fight infection.
  - Lymphocytes: cellular and humoral immunity.
  - Monocytes: phagocytosis of foreign substances and dead cells.
- Platelets (Thrombocytes):
  - Help maintain hemostasis by plugging capillaries and forming clots.
  - Fragments of cytoplasm from megakaryocytes.
- Erythrocytes (Red Blood Cells):
  - Transport oxygen to tissues.
  - Excretee carbon dioxide from tissues.
  - Do not have a nucleus within the RBCs

Cell Types on Peripheral Blood Smears

Erythrocytes (RBCs)
Lymphocytes
Segmented neutrophils
Eosinophils
Monocytes
Platelets
Neutrophilic band
Basophils

CBC Parameter affected by Hemolysis:

WBC- Possibly unaffected
RBC- Possibly Falsely low due to lysis or fragments
HGB- Reportable, accurate measurement relies on RBC being completely lysed
HCT- Falsely low, calculated with invalid MCV, and falsely low RBC.
MCV- Falsely low or high depending on the degree of hemolysis
MCH- Invalid, calculated with falsely low RBC count
MCHC- Invalid, calculated with a falsely low HCT
RDW- Falsely high due to RBC fragments
PLT-Falsely high due to RBC fragments being incorrectly counted as platelets

Sample and Storage Requirements

Sample: Whole blood, non-hemolyzed, avoiding clots.
Anticoagulant: K2 or K3 EDTA.
Storage: Room temperature for up to 1 day and up to 4°C for longer preservation, but cold may induce agglutination.

Erythrocyte and Neutrophil Changes in Aging EDTA Samples.

Erythrocytes: Hypochromic, schistocytes, elliptocytes, spherocytes, crenated
Neutrophils: Smudge/basket cells, cytoplasm rupture, pyknotic nuclei, loss of granulation, cytoplasmic vacuoles, loss of shape/chromatin

Observations from Aged EDTA

Microscopic image/illustration of aged EDTA sample showing changed blood cell morphology.

Reference Ranges

Vary according to age, race, sex, and geographic location.
Established by individual facilities to account for patient population.

Overview of Laboratory Testing

Complete Blood Count (CBC):
- Measures WBC, RBC, hemoglobin, hematocrit, and platelets.
- Calculates RBC indices.
- WBC differential enumerates WBC types and assesses RBC morphology and platelets.
- Indications: fatigue, weakness, infection, inflammation, bruising, bleeding.

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Description

This quiz covers the essential aspects of hematology, including the study of blood cells, hemostasis, and hematopoiesis. It also discusses the functions of the hematology lab and the composition of blood. Test your knowledge on these foundational topics in blood science.