Podcast
Questions and Answers
In the context of erythrocyte sedimentation rate (ESR), what is primarily responsible for maintaining red blood cells (RBCs) in suspension within the plasma?
In the context of erythrocyte sedimentation rate (ESR), what is primarily responsible for maintaining red blood cells (RBCs) in suspension within the plasma?
- The continuous circulation of blood and the negative charge imparted by sialic acid on the RBC membrane. (correct)
- The electrostatic attraction between positively charged plasma proteins and the RBC membrane.
- The high concentration of albumin in the plasma, which increases the viscosity and supports RBC suspension.
- The hydrophobic interactions between RBC surface proteins and plasma lipids.
How does an increased red blood cell (RBC) mass, achieved through rouleaux formation, affect the density and sedimentation rate of RBCs?
How does an increased red blood cell (RBC) mass, achieved through rouleaux formation, affect the density and sedimentation rate of RBCs?
- It reduces both the density and the sedimentation rate of RBCs by disrupting the normal charge distribution on the cell surface.
- It increases the density of RBCs by disproportionately increasing mass relative to surface area, accelerating the sedimentation rate. (correct)
- It has no significant effect on the density of RBCs but slows down sedimentation due to increased viscosity.
- It decreases the density of RBCs by increasing the surface area, leading to a slower sedimentation rate.
What is the underlying biophysical mechanism by which fibrinogen and globulins contribute to rouleaux formation, and how does this affect the erythrocyte sedimentation rate (ESR)?
What is the underlying biophysical mechanism by which fibrinogen and globulins contribute to rouleaux formation, and how does this affect the erythrocyte sedimentation rate (ESR)?
- They neutralize the negative charge on RBCs, reducing repulsion and allowing cells to stick together, increasing ESR. (correct)
- They bind directly to hemoglobin, increasing the density of RBCs and decreasing ESR.
- They increase the negative charge on RBCs, promoting repulsion and slower ESR.
- They alter the membrane permeability of RBCs, causing them to swell and aggregate, leading to a faster ESR.
In the context of the Westergren method for measuring ESR, what is the most critical factor in ensuring accurate and reliable results?
In the context of the Westergren method for measuring ESR, what is the most critical factor in ensuring accurate and reliable results?
Consider a patient with multiple myeloma. How does this condition typically influence the erythrocyte sedimentation rate (ESR), and through what specific mechanism?
Consider a patient with multiple myeloma. How does this condition typically influence the erythrocyte sedimentation rate (ESR), and through what specific mechanism?
How do acute and chronic infections differentially impact the levels of fibrinogen and gamma globulins, and what is the resultant effect on the erythrocyte sedimentation rate (ESR)?
How do acute and chronic infections differentially impact the levels of fibrinogen and gamma globulins, and what is the resultant effect on the erythrocyte sedimentation rate (ESR)?
How does the principle of inclined tubes in automated ESR systems enhance the determination of the sedimentation rate, and what advantage does this offer over traditional methods?
How does the principle of inclined tubes in automated ESR systems enhance the determination of the sedimentation rate, and what advantage does this offer over traditional methods?
In cases of significant tissue damage, such as in rheumatic fever or heart attack, how does the increase in fibrinogen levels affect rouleaux formation and, consequently, the ESR?
In cases of significant tissue damage, such as in rheumatic fever or heart attack, how does the increase in fibrinogen levels affect rouleaux formation and, consequently, the ESR?
How does the presence of a significant number of red blood cells (RBCs) affect the speed at which other RBCs fall in the plasma, and under what condition would the RBCs cease to fall altogether?
How does the presence of a significant number of red blood cells (RBCs) affect the speed at which other RBCs fall in the plasma, and under what condition would the RBCs cease to fall altogether?
Why do women and the elderly typically exhibit higher erythrocyte sedimentation rate (ESR) values compared to men and younger adults, respectively?
Why do women and the elderly typically exhibit higher erythrocyte sedimentation rate (ESR) values compared to men and younger adults, respectively?
Flashcards
Erythrocyte Sedimentation Rate (ESR)
Erythrocyte Sedimentation Rate (ESR)
The speed at which red blood cells (RBCs) settle in plasma over a specific time period.
Why are RBCs suspended in plasma?
Why are RBCs suspended in plasma?
Keeps RBCs suspended due to constant motion and a negative charge on the RBC surface from sialic acid.
Rouleaux Formation
Rouleaux Formation
A phenomenon where RBCs stack together like coins, increasing their mass and sedimentation rate.
What causes Rouleaux Formation?
What causes Rouleaux Formation?
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Conditions increasing Fibrinogen or γ Globulins
Conditions increasing Fibrinogen or γ Globulins
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Westergren Pipette
Westergren Pipette
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Fibrinogen
Fibrinogen
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Factors that govern the speed of falling RBC(s)
Factors that govern the speed of falling RBC(s)
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Study Notes
Erythrocyte Sedimentation Rate (ESR)
- ESR is a common lab test in clinical medicine
- It screens for the presence or absence of active disease
- The test is nonspecific and increases in a variety of diseases
- ESR measures the speed of red blood cell (RBC) sedimentation in plasma
- RBCs have a higher specific gravity than plasma
- RBCs fall to the bottom of a blood tube at room temperature at a certain speed
- The speed at which they fall is the rate of sedimentation
RBC Suspension in Plasma
- Blood circulation keeps RBCs suspended due to constant motion
- RBC surfaces have a negative charge from sialic acid that keeps them suspended
Factors Governing RBC Falling Speed
- The quantity of RBCs in the blood is a governing factor
- Fewer RBCs leads to a higher speed of falling
- Anemia (low RBCs) increases the speed of falling
- Polycythemia (high RBCs) slows or stops the falling
Plasma Viscosity
- Thicker plasma reduces the speed of falling
- Plasma thickness is affected by: Albumin, globulins, and fibrinogen
- Increased plasma proteins increase viscosity and reduce RBC falling speed
Red Blood Cell Mass
- RBC mass is the primary determinant
- A greater RBC mass increases the speed of falling
Rouleaux Formation
- RBC mass increases through rouleaux formation; where RBCs stack like coins
- RBC density is greater than plasma, especially when surface charge alterations cause aggregation
- Altered surface charges results in RBCs aggregating to form rouleaux
- RBCs stick together, multiplying mass while minimally increasing surface area, boosting density
Causes of Rouleaux Formation:
- Fibrinogen is the most important factor
- Globulins also affect rouleaux formation
- Albumin does not cause rouleaux formation
Conditions Increasing Rouleaux Formation
- Increased fibrinogen or gamma globulins increase rouleaux formation and sedimentation rate.
- Fibrinogen and globulins neutralize the negative charge on RBCs, allowing them to stick.
Conditions Increasing Fibrinogen or Gamma Globulins
- Acute and Chronic infections cause an increase in γ globulins
- Tissue damage (rheumatic fever, heart attack) increases fibrinogen levels
- Fibrinogen is an acute phase reactant and increases due to stress or inflammatory conditions
- Plasma cell cancers (Multiple Myeloma) increase γ globulins, leading to high ESR levels
Westergren's Method Procedure
- Uses a Westergren pipette calibrated in mm from 0-200 mm
- The pipette is filled with anticoagulated blood to the zero mark
- Let it stand for one hour in a special rack
- The meniscus separating the RBC layer and plasma is read after one hour in mm/hour
ESR Values
- Women and the elderly typically have higher ESR values
Reference Ranges for ESR in Healthy Adults
- For adults under 50 years old, men should be from 0-15 mm/hr and women should be from 0-20 mm/hr
- For adults over 50 years old, men should be from 0-20 mm/hr and women should be from 0-30 mm/hr
Automated ESR Method
- Automated ESR determination uses the same principles as the standard method
- It uses inclined tubes to accelerate sedimentation rate
- Readings are optically determined and results are reported in mm/hr with a shorter 20-minute test
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