HEMA PRELIMS LAB: Platelet Count (Indirect Method)

Cells which are active in blood coagulation.

Platelets

Functions of platelets

1. Aids in vasoconstriction

2. Formation of Hemostatic Plug

3. Thromboplastic Activity

4. Clot Retraction

The smallest formed elements in the blood.

Platelets

Size of Platelets

2-4µm

Platelets are difficult count due to its affinity for adhering to glass. What is this property called?

Adhesiveness

Platelets are difficult to count due to their tendency to clump together. what is this property of platelets called?

Aggregation

In what objective is indirect platelet count performed?

OIO

How many OIO fields should be done in indirect platelet count?

10 consecutive OIO fields.

Stain used to visualize platelets in indirect platelet count.

Wright’s or Wright-Giemsa Stain

The sequential process by which multiple plasma enzymes and cofactors interact in sequence, forming an insoluble fibrin clot

Coagulation

The smallest formed elements in blood.

Platelets

Platelets are also known as

thrombocytes

A reactive decrease in the blood vessel diameter.

vasoconstriction

What does vasoconstriction of blood vessels control?

1. Blood pressure

2. primary hemostasis

3. distribution of blood throughout the body

Tube of choice for indirect platelet count

EDTA evacuated tube

Total Magnification of the objective where Indirect Platelet Count is done

1000x.

Magnification of the objective where Indirect Platelet Count is done

100x

Each platelet seen per oil power field is equivalent to?

20,000 platelets/mm³

A normal platelet count consists of how many platelets in one OIF?

7-20

Reference Range for Platelet Count

150,000 to 350,000 platelets/mm³

Formula for Platelet Count

Normal Platelets

Identify the platelet morphology and the condition where it is found.

Agranular and Hypgranular Platelets in MDS

Identify the platelet morphology

Giant Platelets

Identify the platelet morphology and in which condition it is found

Platelet Anisocytosis with LARGE platelets and ABNORMAL granulation; Primary Myelofibrosis

Identify the platelet morphology and condition where it is found

Platelet Anisocytosis with GIANT platelet and granulation ANOMALIES; seen in Essential Thrombocythemia

Identify the platelet morphology

Platelet Sattelitosis

Tubes to be recollected in Platelet Sattelitosis

Citrate then EDTA

Identify the platelet morphology and condition where it is found

TINY PLATELETS (microthrombocytes) in a thrombocytopenic patient with WISKOTT- ALDRICH SYNDROME

Identify the platelet morphology and condition where it is found

Giant Bizarre Platelets platelet with cytoplasmic vacuolization in a patient with MDS (Myelodysplastic Syndrome)

Identify the platelet morphology and condition where it is found

LARGE PLATELET in a patient with Bernard- Soulier Syndrome

Identify the platelet morphology and condition where it is found

GIANT ADENDRITIC PLATELET, exceeding the size of background RBCs in a patient with MAY- HEGGLIN ANOMALY

Identify the platelet morphology and condition where it is found

Spectrum of platelet morphology in MYELOPROLIFERATIVE NEOPLASM

Identify the platelet morphology and condition where it is found

LARGE PLATELET with normal granularity in a patient with IMMUNE THROMBOCYTOPENIC PURPURA (ITP)

GIVE THE FOLLOWING RANGE OF VALUES OF PLATELET ESTIMATES:

Markedly decreased
Moderately decreased
Slightly decreased
Low Norma
Normal
Slightly Increased
Moderately Increased
Markedly Increased

Markedly decreased: 0-49,000/μL
Moderately decreased: 50,000-99,000/μL
Slightly decreased: 100,000-149,000/μL
Low Normal: 150,000-199,000/μL
Normal: 200,000-400,000/μL
Slightly Increased: 401,000-599,000/μL
Moderately Increased: 600,000-800,000/μL
Markedly Increased: > 800,000/μL