ESR

Question 1

The ________is an important hematological test that measures the rate at which red blood cells (RBCs) settle in a column of anticoagulated blood over one hour.

Answer 1

erythrocyte sedimentation rate (ESR)

Question 2

ESR

It serves as an indicator of______ but is not disease-specific.

The test is commonly used in clinical laboratories to monitor inflammatory diseases, infections, malignancies, and autoimmune disorders.

Answer 2

inflammation

Question 3

He observed that plasma proteins influenced the sedimentation of RBCs, but his work was largely ignored due to the shift in medicine toward cellular pathology.

Answer 3

Nasse

Question 4

He is a Swedish physician____ which recognized the clinical significance of ESR in pregnancy and inflammation.

Answer 4

Fahraeus

Question 5

Who standardized the ESR method, which was later adopted by the Clinical and Laboratory Standards Institute (CLSI) as the reference method?

Answer 5

Westergren

Question 6

When anticoagulated blood is left undisturbed in a vertical tube at room temperature, RBCs settle at the bottom due to____.

The distance they fall in one hour is recorded as the ESR, measured in________.

Answer 6

gravity

millimeters per hour (mm/hr).

Question 7

The rate of sedimentation is influenced by:

Answer 7

1. Erythrocyte factors – Size, shape, and number of RBCs
2. Plasma factors – Levels of fibrinogen and globulins
3. Mechanical and technical factors – Tube size, angle, temperature, and vibrations

Question 8

RBCs have a_______, which causes them to repel each other, preventing rapid settling.

Answer 8

negative charge (zeta potential)

Question 9

Increased_______

•	These act as bridges between RBCs, overcoming the zeta potential and causing\_\_\_\_\_\_.

Answer 9

Plasma Proteins (e.g., Fibrinogen, Globulins)

rouleaux formation (RBCs stacking like coins)

Question 10

• _____increases RBC mass, leading to faster sedimentation and a higher ESR.

Answer 10

Rouleaux

Question 11

• Inflammation and infections increase________, leading to a higher ESR.

• Abnormal RBC shapes (e.g.,2) prevent rouleaux formation and result in a lower ESR.

Answer 11

acute-phase reactants (fibrinogen, C-reactive protein, immunoglobulins)

sickle cells, spherocytes

Question 12

ESR is useful in monitoring but not diagnosing specific diseases.

It is often used alongside other tests like _______for better accuracy.

Answer 12

C-reactive protein (CRP)

Question 13

There are several ways to measure ESR, but the _____is the gold standard.

Answer 13

Westergren method

Question 14

Westergren Method (Standard CLSI Method)

1. Collect venous blood using EDTA (anticoagulant).
2. Mix blood with____.
3. Fill _____-long Westergren tube up to the zero mark.
4. Place the tube vertically in a stand at_____.
5. Read the ESR after 1 hour (distance RBCs have settled in mm).

Answer 14

3.8% sodium citrate (4:1 ratio)

200 mm

room temperature (18–25°C)

Question 15

• Advantages:
• Internationally standardized
• Accurate and reproducible

• Disadvantages:
• Time-consuming (requires 1 hour)
• Manual handling errors

Answer 15

Westergren Method (Standard CLSI Method)

Question 16

• Uses pre-diluted blood and an automated reader, reducing errors.
• Faster and commonly used in modern labs.

Answer 16

Modified Westergren Method

Question 17

• Uses a shorter 100 mm tube (instead of 200 mm).
• Less sensitive but useful for detecting low ESR values.

Answer 17

Wintrobe Method

Question 18

• Faster (results in minutes) and reduce errors from manual methods.
• Some devices use optical density or rheology-based techniques to estimate ESR.

Answer 18

Automated ESR Analyzers

Question 19

Anticoagulants Used
•_________: Maintains a 4:1 blood-to-anticoagulant ratio for accurate results.

•______: If used, blood must be diluted with 0.9% sodium chloride in a 4:1 ratio.

Answer 19

Sodium citrate (preferred)

EDTA

Question 20

Specimen Handling

• Blood must be at_____ for testing.
•____ samples (≤2 hours old) are ideal.
• _______must be rewarmed before testing.
•_____ specimens are not acceptable.

Answer 20

room temperature (20°C–25°C)

Fresh

Refrigerated blood (≤6 hours old)

Hemolyzed

Question 21

Reagents, Supplies, and Equipment

• _______– Used to measure ESR.

• _______– Holds tubes upright to prevent errors. It must have a leveling device to ensure accuracy.

Answer 21

Westergren pipettes

Vertical ESR rack

Question 22

Improper Specimen Handling

• Blood too old (>2 hours at room temperature or >6 hours refrigerated) can affect RBC shape, leading to false______ESR.

• Hemolyzed samples alter results and are unusable.

Answer 22

false low

Question 23

Physical and Environmental Factors
• Tube tilt: Even a____ angle can increase ESR by___% due to RBCs settling faster.
• Temperature: The test must be performed at______
• ____and drafts can disrupt RBC settling.

Answer 23

3°; 30%

20°C–25°C

Vibrations

Question 24

The_______ is the most widely used manual ESR method due to its high sensitivity and reliability.

It is recommended by the (2)

Answer 24

Modified Westergren method

International Council for Standardization in Hematology (ISCH) and the Clinical and Laboratory Standards Institute (CLSI)

Question 25

Advantages of the Modified Westergren Method (4)

Answer 25

1. Increased Column Height (200 mm Tube) • Allows for the detection of highly elevated ESR values. 2. Standardized and Internationally Accepted • Ensures greater accuracy and reproducibility across laboratories. 3. Compatible with EDTA Blood Samples • Prevents clotting artifacts that could interfere with ESR measurement. 4. More Sensitive than the Wintrobe Method • Due to the longer column, it can better detect even subtle elevations in ESR.

Question 26

Advantages of the Wintrobe Method (3)

Answer 26

1. Shorter Column Height (100 mm Tube) • Reduces the effect of excessive rouleaux formation, which may cause falsely high readings in Westergren. 2. Detects Slight ESR Elevations More Accurately • The shorter sedimentation column makes small changes in ESR more noticeable. 3. Less Affected by Extreme Anemia • Anemia can falsely elevate ESR due to decreased RBC count. The Wintrobe method minimizes this effect.

Question 27

Disadvantages of the Wintrobe Method (3)

Answer 27

• Lower Sensitivity for Markedly Elevated ESR • The 100 mm column is shorter, so extremely high ESR values may not be accurately detected. • More Labor-Intensive Sample Preparation • Requires careful pipetting and precise filling to avoid air bubbles. • Not the Standard ESR Method • Due to lower international standardization, it is less commonly used in clinical laboratories.

Question 28

The_____ is useful for detecting small ESR increases but lacks sensitivity for extremely high ESR values.

Answer 28

Wintrobe method

Question 29

• Anemic patients may have an ESR that appears_____ due to lower RBC concentration. • Patients with abnormally shaped RBCs (sickle cells, spherocytes) may have ____ESR due to lack of rouleaux formation. • Polycythemia slows ESR, while increased plasma proteins (e.g., in infections, multiple myeloma) accelerate ESR.

Answer 29

falsely high falsely low

Question 30

Improper Specimen Handling • Blood too old (>2 hours at room temperature or >6 hours refrigerated) can affect RBC shape, leading to false______ESR. • Hemolyzed samples alter results and are unusable.

Answer 30

false low

Question 31

have been developed to simplify and standardize ESR testing. These kits typically include a pre-calibrated column with a safety cap, ensuring precise blood filling to the 0 mm mark.

Answer 31

Disposable commercial kits

Question 32

The safety cap eliminates manual errors in setting the blood level at 0 mm. Since the system is closed, it reduces exposure to bloodborne pathogens, ensuring laboratory safety. Pre-marked and standardized tubes prevent volume discrepancies that may affect ESR readings. The kits are designed for ease of use, reducing the need for complex equipment.

Answer 32

Disposable ESR kits

Question 33

• Cost: More expensive than manual Westergren and Wintrobe methods. • Limited Compatibility: Some kits may require specific racks or equipment. • Single-use: Not reusable, leading to more waste production.

Answer 33

Disposable ESR kits

Question 34

have revolutionized sedimentation rate testing by incorporating advanced technologies such as centrifugation, photometry, and microflow analysis. These systems improve efficiency, precision, and safety.

Answer 34

Automated ESR systems

Question 35

Some automated analyzers use_______ to accelerate RBC sedimentation, allowing for faster results than traditional 1-hour methods. The machine measures how quickly RBCs settle when exposed to controlled centrifugal force.

Answer 35

centrifugation Centrifugation-Based Automated ESR

Question 36

• This system does not use gravity to measure ESR. Instead, it employs a quantimetric photometric method where: • A small blood sample is drawn from an EDTA tube. • The sample flows into a microfluidic cell, where RBC rouleaux formation is measured. • The size of the RBC aggregates (rouleaux) is directly proportional to the ESR value.

Answer 36

Photometric ESR Analysis (Example: iSED by Alcor Scientific)

Question 37

Faster Turnaround Time Reduces test duration from 1 hour to minutes, improving laboratory efficiency. Smaller Sample Volume Requires less blood, beneficial for pediatric or anemic patients. Automated Sampling & Mixing Minimizes manual handling, reducing human errors. Built-in Quality Control (QC) Ensures accuracy and detects pre-analytical errors. Specimen Identification Can scan barcodes or QR codes, reducing sample mix-ups. Laboratory Information System (LIS) Interface Allows direct integration with hospital or lab databases. Minimized Contamination Risk Closed systems limit biohazard exposure.

Answer 37

Automated ESR Systems

Question 38

• Expensive: High initial cost for purchase and maintenance. • Requires Calibration: Must be regularly validated against the Westergren method for accuracy. • May Be Sensitive to Interferences: Some analyzers are more affected by hemolysis, lipemia, or icterus than traditional methods.

Answer 38

Automated ESR Systems

Question 39

The _______ is widely used as an indirect marker of inflammation. It measures how quickly red blood cells (RBCs) settle in a vertical tube over one hour.

Answer 39

erythrocyte sedimentation rate (ESR)

Question 40

Inflammatory reactions increase the ESR due to…??…

Answer 40

changes in plasma protein composition, particularly acute-phase reactants like fibrinogen and globulins, which promote rouleaux formation (stacking of RBCs).

Question 41

How Inflammation Increases ESR? Release of Acute-Phase Reactants

Answer 41

Inflammatory conditions trigger the liver to produce fibrinogen, C-reactive protein (CRP), and globulins. These positively charged proteins neutralize the RBCs’ negative surface charge, allowing them to stick together and form rouleaux.

Question 42

Rouleaux Formation. Explain

Answer 42

Normally, RBCs repel each other due to their negative charge (zeta potential). In inflammation, increased fibrinogen and globulins overcome this repulsion, leading to RBC stacking. Rouleaux are denser than individual RBCs, so they settle faster, leading to an elevated ESR.

Question 43

_____:Indirect (measures RBC sedimentation) _____:Direct (measures CRP levels in blood)

Answer 43

ESR CRP

Question 44

ESR CRP Speed of Response?

Answer 44

Slower (peaks in 24-48 hours) Faster (peaks in 6-8 hours)

Question 45

ESR CRP Specificity

Answer 45

Less specific (affected by anemia, pregnancy, etc.) More specific for inflammation

Question 46

ESR CRP Use in Acute Inflammation

Answer 46

Less sensitive More reliable

Question 47

ESR CRP Use in Chronic Inflammation

Answer 47

Good for monitoring long-term inflammation Good for detecting acute flare-ups

Question 48

_____is a better marker for acute inflammation, while_____ is more useful for monitoring chronic inflammatory conditions like autoimmune diseases.

Answer 48

CRP ESR

Question 49

More specific tests like CRP exist, but ESR is still widely used because it is…?

Answer 49

simple, inexpensive, useful for chronic inflammation, and complements other tests.

Question 50

Instead of replacing ESR, newer tests like______ and_____ are used alongside it for a more comprehensive assessment of inflammation.

Answer 50

CRP and procalcitonin

Question 51

– Used to measure ESR. – Holds tubes upright to prevent errors. It must have a leveling device to ensure accuracy.

Answer 51

Westergren pipettes Vertical ESR rack

Question 52

ESR is directly proportional to the____ and inversely proportional to_____

Answer 52

RBC mass plasma viscosity