Acute Myeloid Leukemia (AML) Overview

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Questions and Answers

What causes changes in electrical resistance when cells pass through an aperture?

The conductive solution

The cell's internal constituents

The cell's displacement of an equal volume of conductive fluid (correct)

The high-frequency electromagnetic probe

What is the purpose of diluting blood in an isotonic conductive solution?

To change the electrical resistance

To increase the conductivity

To count the voltage pulses

To preserve the cell shape (correct)

What is the principle underlying the counting of cells in an electrical impedance analyzer?

The radiofrequency principle

The cytochemical principle

The electro-optical principle

The Coulter principle (correct)

How does conductivity provide additional information about cells?

By analyzing internal constituents, such as chemical composition and nuclear characteristics Signup and view all the answers

What is unique to the Siemens automated hematology series?

The use of a cytochemical reaction to determine peroxidase activity Signup and view all the answers

What does the height of the voltage pulse generated by a cell depend on?

The cell's volume Signup and view all the answers

What is the purpose of using a combination of electrical impedance and light scattering methods?

To provide an internal comparison Signup and view all the answers

What is measured by the light-sensitive detector in electro-optical analyzers?

The light scattering proportional to the size of the particles Signup and view all the answers

What is the clinically established threshold to classify a patient as diabetic?

7,2 mmol/l Signup and view all the answers

What is the purpose of a test with perfect diagnostic accuracy?

To determine the presence or absence of disease with certainty Signup and view all the answers

What are patients correctly classified as abnormal called?

True-positives (TPs) Signup and view all the answers

Why do false results occur in a test?

Because the two patient populations overlap Signup and view all the answers

What is the term for patients incorrectly classified as normal?

False-negatives (FNs) Signup and view all the answers

What is the purpose of sensitivity and specificity in a test?

To measure the diagnostic accuracy of a test Signup and view all the answers

What is sensitivity in a test?

The ability of a test to detect disease Signup and view all the answers

What happens when an analyte has two relevant cutoffs, such as thyroid-stimulating hormone?

False results are produced Signup and view all the answers

What percentage of toddlers aged 1–2 years in the United States have iron deficiency anemia?

3% Signup and view all the answers

What is the consequence of prolonged treatment of peptic ulcer and acid reflux by H2 blockers and acid pump blockers?

Defective iron absorption Signup and view all the answers

This is an example statement that is true

False Signup and view all the answers

What is the approximate duration for which an adult male's body iron stores would last if he had absolutely no iron intake or absorption?

3–4 years Signup and view all the answers

Example question?

example answer Signup and view all the answers

What is the most common cause of iron deficiency in adult males?

Chronic blood loss Signup and view all the answers

What is the characteristic of red blood cells in early iron deficiency status?

Normochromic and normocytic Signup and view all the answers

The ______ barked

dog Signup and view all the answers

What is the characteristic of red blood cells in later stages of iron deficiency?

Microcytic and hypochromic Signup and view all the answers

Match the following programming languages with their primary usage:

Python = General-purpose programming JavaScript = Client-side scripting for web applications SQL = Database queries CSS = Styling web pages Signup and view all the answers

What is the significance of increased red cell distribution width (RDW) in iron deficiency anemia?

It is a non-specific indicator of iron deficiency anemia Signup and view all the answers

What is the effect of iron therapy on reticulocytes in iron deficiency anemia?

Reticulocytes are increased in absolute numbers Signup and view all the answers

What is the percentage of diseased patients that will have a negative result in a test that is 90% sensitive?

10% Signup and view all the answers

What percentage of patients without diabetes will have a negative result in a fasting glucose test that is 82% sensitive?

100% Signup and view all the answers

A test that is 90% specific will give positive results in what percentage of patients without disease?

10% Signup and view all the answers

What is the main advantage of a test with a higher sensitivity?

It identifies a greater proportion of persons with disease Signup and view all the answers

What is the predictive value of a positive test (PPV)?

The proportion of persons with a positive test who truly have the disease Signup and view all the answers

What percentage of non-cancer patients are classified as true negative in a PSA test with 90% specificity?

90% Signup and view all the answers

A test with a higher specificity is better at:

Excluding people without the disease Signup and view all the answers

What is the result of a test with 90% sensitivity and 90% specificity?

90% of patients with the disease will have a positive result and 90% of patients without the disease will have a negative result Signup and view all the answers

Study Notes

Diagnostic Accuracy

A test with perfect diagnostic accuracy can determine the presence or absence of disease with certainty.
The diagnostic accuracy of a test is determined by comparing the test's ability to discern true disease from nondisease.
Patients correctly classified as abnormal are called true-positives (TPs) and those correctly classified as normal are called true-negatives (TNs).
False results occur because the two populations overlap, and patients incorrectly classified as normal are false-negatives (FNs), and those incorrectly classified as abnormal are false-positives (FPs).

Sensitivity and Specificity

Sensitivity is the ability of a test to detect disease and is expressed as the proportion of persons with disease in whom the test is positive.
A test that is 90% sensitive will give positive results in 90% of diseased patients (TP) and negative results in 10% of diseased patients (FN).
Specificity is the ability to detect the absence of disease and is expressed as the proportion of persons without disease in whom the test is negative.
A test that is 90% specific will give negative results in 90% of patients without disease (TN) and positive results in 10% of patients without disease (FP).

Predictive Value

The predictive value of a positive test (PPV) is the probability that a positive test indicates disease.
PPV is the proportion of persons with a positive test who truly have the disease.

Coulter Principle

The Coulter principle is a method used to count cells by measuring the changes in electrical resistance caused by cells passing through an aperture.
Each cell that passes through the aperture displaces an equal volume of conductive fluid, increasing the electrical resistance and creating a voltage pulse.

Conductivity and Electro-Optical Analyzers

Conductivity is determined using a high-frequency electromagnetic probe that provides information on the cells' internal constituents.
Electro-optical analyzers use a light-sensitive detector to measure light scattering, which is proportional to the size of the particle.

Iron Deficiency Anemia

Iron deficiency anemia occurs after total gastrectomy or subtotal gastrectomy.
Prolonged treatment of peptic ulcer and acid reflux by H2 blockers and acid pump blockers may cause defective iron absorption.
Causes of malabsorption of iron are extremely rare, except for sprue syndrome.
Almost all cases of iron deficiency in adult males are due to chronic blood loss.
Hemorrhagic lesions, medications, and helminthic infections are common causes of iron deficiency in males and postmenopausal females.

Blood Film Characteristics

In early iron deficiency, the stained blood film shows normochromic normocytic erythrocytes.
In later stages, the picture is one of microcytosis, anisocytosis, poikilocytosis, and hypochromia.
Anisocytosis may be identified by automated blood counters as increased red cell distribution width (RDW).