Hematology Quiz: WBC Histogram Analysis

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Questions and Answers

What is the range in which lymphocytes are distributed in a normal WBC histogram?

100-150 fL

25-50 fL

150-300 fL

50-100 fL (correct)

In a normal WBC histogram, where are neutrophils primarily located?

150-300 fL (correct)

50-150 fL

300-400 fL

25-50 fL

How does the RBC and platelet distribution curve differentiate between the two?

By drawing a line through the curve's trough, typically in the 25-30 fL regions (correct)

By using a unique color for RBCs and platelets

By plotting them on different axes

By counting cells above a specific line

What type of cell populations are included in the mixed cell population in a WBC histogram?

Monocytes, basophils, and eosinophils Signup and view all the answers

Which of the following statements about a normal WBC histogram is correct?

It effectively narrows down differential diagnoses early in patient evaluation. Signup and view all the answers

What is the primary factor that affects forward scatter in light-scatter methods?

Cell size Signup and view all the answers

In a three-part differential count, which of the following categories typically includes eosinophils and basophils?

Granulocytes Signup and view all the answers

Which automated blood cell counter type is increasingly common?

Flow cytometry incorporated in blood counters Signup and view all the answers

What is the classification of cells in a five-part or seven-part differential count?

Neutrophils, eosinophils, basophils, monocytes, and lymphocytes Signup and view all the answers

What does the sideward scatter predominantly reflect in cells?

Nuclear segmentation Signup and view all the answers

In a three-part differential count, how are cells typically categorized?

Granulocytes, lymphocytes, monocytes Signup and view all the answers

What characteristic is typically analyzed in automated differential blood counting?

Volume and physical characteristics Signup and view all the answers

Which cell types may be flagged in a three-part differential count despite not being categorized individually?

Eosinophils and basophils Signup and view all the answers

What condition is indicated by a high MCHC value?

Hemolytic anemia Signup and view all the answers

Which factor can cause a spurious increase in MCHC?

Cold agglutinin Signup and view all the answers

What does a normal RDW in the presence of anemia indicate?

Thalassemia trait Signup and view all the answers

Which of the following is NOT a cause of leukopenia?

Thalassemia Signup and view all the answers

What is the normal adult range for neutrophils in white blood cells?

2-7 x10^9/l Signup and view all the answers

Which type of white blood cell is the largest and can differentiate into macrophages?

Monocytes Signup and view all the answers

Leukocytosis may be caused by all of the following EXCEPT:

Aplastic anemia Signup and view all the answers

What is the normal count range for lymphocytes in adults?

1-3 x10^9/l Signup and view all the answers

What is the main reason for enumerating nucleated red blood cells (NRBC) in blood samples?

To ensure accurate white blood cell (WBC) counts. Signup and view all the answers

Which technique is primarily used by instruments to identify NRBC?

Fluorescence laser light scatter or flow cytometry. Signup and view all the answers

What does flagging in a hematology lab signify?

Presence of a significant abnormality in the analysis. Signup and view all the answers

How is hemoglobin measured in some automated counters?

Through the manual method of HiCN with cyanide reagent. Signup and view all the answers

During which phase of the erythrocyte sedimentation rate (ESR) do red blood cells form rouleaux?

Phase 1: Aggregation phase. Signup and view all the answers

What can cause inaccuracies in the morphological correction of the WBC count?

Small nuclear size of NRBC below the detection threshold. Signup and view all the answers

What is the primary role of potassium ferricyanide in the hemoglobin measurement process?

To convert hemoglobin types to HiCN for measurement. Signup and view all the answers

What must be done when a blood sample generates suspect flags during analysis?

Confirm results with microscopic examination. Signup and view all the answers

What is the normal adult platelet count range?

150-450 x10^9/l Signup and view all the answers

Which of the following can cause thrombocytopenia?

Peripheral consumption and destruction Signup and view all the answers

What does an increased Mean Platelet Volume (MPV) indicate?

Increased production rate of platelets Signup and view all the answers

Which condition is associated with thrombocytopenia and low MPV?

Wiskott Aldrich syndrome Signup and view all the answers

In which scenario can pseudo-thrombocytopenia occur?

Presence of platelet clumps Signup and view all the answers

What is the normal range for Plateletcrit (PCT)?

0.22–0.24% Signup and view all the answers

What does the Platelet Volume Distribution Width (PDW) indicate?

Volume variability in platelet sizes Signup and view all the answers

What is the normal range for the Platelet Larger Cell Ratio (P-LCR)?

15–35% Signup and view all the answers

Which of the following conditions is most likely indicated by a low hematocrit level?

Anemia Signup and view all the answers

What does a high mean corpuscular volume (MCV) greater than 98 femtoliters typically indicate?

Macrocytic Anemia Signup and view all the answers

Which of the following best describes the condition when the mean cell hemoglobin (MCH) level is less than 27 picograms per cell?

Iron Deficiency Anemia Signup and view all the answers

Which organ's failure can lead to decreased production of erythropoietin and contribute to anemia?

Kidney Signup and view all the answers

What is the significance of hemoglobin levels greater than normal in the blood?

Suggests polycythemia Signup and view all the answers

What is the normal range of mean corpuscular hemoglobin concentration (MCHC) in g/dl?

32-36 Signup and view all the answers

In which condition would you expect a white blood cell count to be elevated, potentially affecting hematocrit levels?

Leukemia Signup and view all the answers

Which of these scenarios is likely to cause an increase in red blood cell production?

Chronic lung disease Signup and view all the answers

Study Notes

Complete Blood Count (CBC) Interpretation

CBC is the most common test in clinical medicine.
It's used to determine the type and severity of blood cell abnormalities.
Modern CBCs are fully automated and highly reproducible.
Correct CBC interpretation reduces unnecessary blood smears.
It aids in provisional diagnosis of red blood cell (RBC) and white blood cell (WBC) diseases.

Components of Automated CBC

Blood count parameters include hemoglobin (Hb), hematocrit (Hct), red blood cells (RBC), white blood cells (WBC), and platelets.
Red cell indices: Mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), red cell distribution width (RDW).
WBC differentials (granulocytes, lymphocytes, monocytes, eosinophils, basophils, and neutrophils).
Platelets count and indices.
Reticulocyte count.

Advantages of Automation

Increased efficiency and streamlined workflow.
Increased productivity.
Increased test volumes without extra resources.
Reduced turnaround time (TAT) and improved service.
Lower costs.

Basic Principles of Automated Blood Cell Analyzers: Electrical Impedance

Red blood cells are poor conductors of electricity.
Diluents are good conductors.
This difference forms the basis of cell counting systems.
Coulter Principle: The conventional technique for cell counting.
Blood flows through a narrow aperture between two electrodes.
Change in impedance is proportional to cell volume, enabling cell counting and volume measurement.
10,000 cells per second can be counted in typical analysis.
Process takes less than a minute.

Light Scattering

Microscopic particles, like blood cells, scatter incident light into different angles.
Correlating generated optical signals classifies cells in multidimensional spaces.
Forward scatter (low angle) primarily depends on cell size.
Sideward scatter (90 degrees) predominantly reflects nuclear segmentation and cytoplasmic granules.

Automated Differential Count

Modern differential counters use flow cytometry in conjunction with full blood counting.
Automation allows for three-part or five-to seven-part differential counts.
Counts are performed on diluted whole blood, where red blood cells may be lysed or rendered transparent.
Analysis often involves dye binding to granules or cellular enzyme activity (like peroxidase).

Three-Part Differential

Categorizes cells as granulocytes ("large cells"), lymphocytes ("small cells"), and monocytes ("middle cells").
In practice, some eosinophils and basophils may be counted in the monocyte category.
Some three-part diffs categorize leukocytes by ratio (small, middle, large).

Five and Seven-Part Differentials

Classifies blood cells further, including immature granulocytes, blasts, and atypical lymphocytes.
Automated instruments can flag potential abnormalities with elevated numbers of certain cell types.
Often counts neutrophils, eosinophils, basophils, lymphocytes, monocytes, and sometimes, additional cell types.

Automated Nucleated Red Blood Cell (NRBC) Count

NRBCs affect white blood cell (WBC) accuracy in some counting machines.
Historically, NRBC enumeration was done manually via blood smears.
Automated methods stain NRBCS and distinguish them from WBCs; if nuclear size is too small, then it is not distinguishable.

Flagging of Automated Blood Counts

A "flag" signals inconsistencies in machine analysis.
Operators need manual verifications if flagged.
Flags occur when analyzer detects possible abnormalities, and microscopic examination is needed.

Measurement of Hemoglobin

Some machines measure hemoglobin (Hb) by modifying the cyanide method (HiCN).
They dilute blood with reagents like potassium cyanide and ferricyanide.
Hemoglobin (Hi and HbCO) are converted to HiCN, absorbance at 540 nm is measured.

Erythrocyte Sedimentation Rate (ESR)

Measures how quickly red blood cells settle in plasma.
Consists of 3 phases: aggregation, sedimentation, and packing.
Factors affecting speed: plasma protein composition, erythrocyte size/shape, erythrocyte concentration.
Elevated ESR is common in inflammatory diseases, while low ESR can be tied to conditions with few/small or abnormal red cells.

RBC indices

RBC count: Measures the actual number of red blood cells, normal for adults male = 5 +/- 0.5, females = 4.3 +/- 0.5
Low RBC count: Often indicative of anemia due to blood loss, impaired production, or increased destruction.

Hematocrit (HCT):

The ratio of red blood cells to the total blood volume.
Expressed as a percentage.
High or low HCT correlates with high or low RBC counts.
Normal range differs between males and females.

Higher than Normal Hematocrit

Abnormal increase in red blood cells (erythrocytosis).
Conditions like polycythemia vera.
Low oxygen levels (hypoxia), may be observed at high altitudes or due to heart/lung diseases, body increases red blood cells to compensate for low oxygen.

Lower than Normal Hematocrit

Insufficient supply of healthy red blood cells (anemia).
Long-term illness, infection, leukemia, lymphoma, and other blood disorders.
Acute kidney disease leading to reduced production of red blood cells.
Pregnancy (additional fluid retention).

Hemoglobin (Hb)

The protein in red blood cells that carries oxygen.
Normal ranges vary by age and sex.
Low levels indicate anemia, high levels indicate polycythemia.

Mean Corpuscular Volume (MCV)

Average volume of red blood cells.
Important for classifying anemia (microcytic, normocytic, or macrocytic).
Based on hematocrit and red blood cell count.

Mean Cell Hemoglobin (MCH)

Average mass of hemoglobin per red blood cell.
Calculated using hemoglobin level and red blood cell count.
Low levels commonly associated with iron-deficiency anemia.

Mean Corpuscular Hemoglobin Concentration (MCHC)

Concentration of hemoglobin in a defined volume of red blood cells.
Low levels (hypochromic) often reflect iron-deficiency anemia.
High levels (hyperchromic) are uncommon but may occur in situations like autoimmune hemolytic anemia.

Red Cell Distribution Width (RDW)

Measures variation in red blood cell size.
Aids in differentiating anemia types (single cause vs. mixed causes).
High RDW often seen in conditions like iron-deficiency anemia or conditions with mixed causes of anemia for example, anemia of chronic disease or thalassemia.

WBC/Differential Count

Normal WBC counts differ by age (usually higher in children).
Low WBC counts (leukopenia) can arise from various factors (infection, drug use, certain cancers).
High WBC counts (leukocytosis) can result from infections, inflammation, certain cancers, or other causes.

Platelet (PLT) Count

Normal platelet counts range differently in adults and children.
Elevated counts (thrombocytosis) may result from reactive conditions, or be associated with blood cancers, inflammatory conditions, infections, and reactive processes.
Low counts (thrombocytopenia) are tied to processes such as platelet consumption, failure of production, or peripheral destruction.

Platelet Indices

Plateletcrit (PCT): Percentage of blood occupied by platelets.
Mean platelet volume (MPV): Average volume of platelets.
Platelet volume distribution width (PDW): Variability in platelet size.
Platelet larger cell ratio (P-LCR/PLCR): Percentage of larger platelets in circulation.

Histogram

Visual representation of blood cell distribution.
Helps identify possible anomalies in cell size, shape, and counts that may lead to blood disorders.
The histogram can show abnormal ranges for various cell types.

WBC Histogram

Illustrates distribution of different white blood cell types, such as lymphocytes, monocytes, and neutrophils (and basophils and eosinophils).
Normal graphs show different patterns based on expected cell distribution.

RBC and Platelet Distribution Curve

Blood cells (RBCs and platelets) are counted together.
A line separates platelet and red blood cell regions in a histogram.

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Description

Test your knowledge on the distribution of lymphocytes, neutrophils, and other cell populations in a normal WBC histogram. This quiz covers essential concepts related to automated blood cell counters and cellular scatter analysis methods. Perfect for students in hematology and related fields!