Hematology: Platelet Clumping Issues

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Questions and Answers

What is the primary reason for performing a blood count using a 3.2% sodium citrate tube instead of using EDTA?

To ensure accurate measurement of platelet and leukocyte counts (correct)

To increase the platelet count significantly

To decrease the volume of blood needed for the test

To prevent artifacts during slide preparation

Which of the following describes a characteristic of pseudothrombocytopenia?

Low platelet counts that are misreported as elevated white blood cell counts (correct)

Elevated platelet counts resulting from sample contamination

High platelet count falsely reported due to inferior laboratory techniques

Inaccurate leukocyte counts due to overlapping platelet clumps

What is the effect of an incorrect angle when using the two-glass slide method for blood film preparation?

It has no effect on smear quality.

Both high and low angles result in unusable smears.

A high angle results in a thin smear, while a low angle results in a thick smear.

A low angle produces a thin smear, while a high angle results in a thick smear. (correct)

What is a disadvantage of using anticoagulant-free blood from a finger prick?

The limited amount of blood makes it challenging to prepare multiple films. Signup and view all the answers

What is the ideal length of a blood smear film when using the wedge method?

2/3 to 3/4 the length of the film Signup and view all the answers

What does an increase in hematocrit require when preparing a blood smear?

Decrease the angle as low as 25° Signup and view all the answers

What is a common issue found with blood smears that have uneven distribution of white blood cells?

Concentration of monocytes in the feathered edge Signup and view all the answers

Which of the following best describes the ideal shape of a blood smear?

Finger-shaped with clear edges Signup and view all the answers

What is the effect of spreading the blood smear too slowly?

Results in a thinner smear with poor distribution of WBCs Signup and view all the answers

What is one advantage of using the centrifugal (spinner) type preparation method?

Creates a consistent preparation of blood cells. Signup and view all the answers

Which solution is NOT necessary for blood film staining?

Distilled alcohol Signup and view all the answers

In Romanowsky-type stains, which component is primarily responsible for coloring the nucleus blue/purple?

Methylene blue Signup and view all the answers

What is the main purpose of using fixative in blood film preparation?

To preserve cellular morphology. Signup and view all the answers

Which automated instrument is primarily used for both slide making and staining?

Coulter LH Signup and view all the answers

Why is it important to use non-anticoagulated blood for certain automated methods?

It allows for a more even distribution of blood cells. Signup and view all the answers

When manually preparing a blood smear, what is the ideal time to leave the Wright's stain on the slide?

1-3 minutes Signup and view all the answers

Which of the following statements is true regarding the Sysmex SP-10?

It is used for both slide preparation and staining. Signup and view all the answers

What is a likely cause of eosinophil granules appearing gray in a blood smear?

Buffer was too basic Signup and view all the answers

Which unusual finding in a blood smear could indicate a patient with increased lipid levels?

Blue specks at the feather edge Signup and view all the answers

What appearance would indicate that the red blood cells in a blood smear might be improperly stained?

Pale or red in color Signup and view all the answers

When examining a blood smear, what would a grainy appearance typically indicate?

Improper slide preparation Signup and view all the answers

Which of the following is NOT a common problem encountered in blood smear staining?

High fluorescence Signup and view all the answers

What should be avoided when using the 40x high-dry objective for WBC count estimation?

Viewing the thick portions of the smear Signup and view all the answers

Which of the following factors influences the rejection of a blood smear film during microscopic examination?

Presence of more than four times the usual number of WBCs at the lateral edges Signup and view all the answers

What is the primary use of the 100x oil immersion objective during a blood smear examination?

To analyze nuclear details of leukocytes Signup and view all the answers

When estimating the WBC count using the 40x high-dry objective, how is the final count calculated?

Average no. of WBCs per field multiplied by 2,000 Signup and view all the answers

What indicates a potential problem when observing RBCs in the feathered edge while using the 40x objective?

RBCs appear macrocytic and flattened Signup and view all the answers

What is the estimated platelet count per µL if the average observed platelets in ten fields using the 100x objective is 150?

3,000,000/µL Signup and view all the answers

During microscopy, which condition would require a separate process for transferring observations from the 10x objective to the 100x objective?

Incompatibility of findings across different magnifications Signup and view all the answers

What characteristic should be noticed when examining the ideal area of a blood smear under the 10x low power objective?

RBCs near each other but not overlapping Signup and view all the answers

Study Notes

EDTA-Induced Platelet Clumping

EDTA (ethylenediaminetetraacetic acid) can cause platelets to clump together, appearing as large clumps, similar in size to white blood cells (WBCs).
This can cause a falsely low platelet count.

Pseudothrombocytopenia

A falsely low platelet count due to the effects of EDTA.
The incorrect counts occur because the anticoagulant EDTA causes clumping of platelets, making them appear fewer in numbers.

Pseudoleukocytosis

A falsely elevated white blood cell (WBC) count.
Large platelets might be misidentified as WBCs, leading to a higher WBC count as determined by a manual count.

Case Study

Initial platelet count was 90,000/mm³.
Initial leukocyte count was 15,000/mm³.
Platelet clumps were observed on blood smear.
Blood recollected using sodium citrate.
Second platelet count was 115,000/mm³.
Second WBC count was 11,000/mm³.
Correct final platelet count: 126,500/mm³.
Correct final WBC count: 12,100/mm³.

Anticoagulant-Free Blood (Finger Prick)

Advantages:
- Performed at the patient's side, minimizing delays and complications.
- Can sometimes prevent artifacts.
Disadvantages:
- Platelets can clump, leading to inaccuracies.
- Few well-prepared blood films can be made, when finger pricks have healed.

Blood Film Preparation Methods

Two-glass slide method (Manual Wedge Technique): Most frequently used
- Materials: Pusher slide (aka: spreader), film slide
- Procedure: The angle between the two slides should be between 30° and 45°, to create thiner or thicker smears.
- Quality Control: The angle of the spreader determines smear thickness(too high leads to thicker smears, too low leads to thinner smear).

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Description

Explore the phenomena of EDTA-induced platelet clumping and its implications for blood count accuracy. This quiz covers pseudothrombocytopenia and pseudoleukocytosis through a detailed case study, illustrating the importance of proper anticoagulant use. Test your knowledge on interpreting laboratory results affected by these issues.