Manual Platelet Count (direct method)

Question 1

Often hard to differentiate from bacteria and debris

[platelet are difficult to count due of this]

Answer 1

Small size

Question 2

Affinity for adhering to glass.

[platelet are difficult to count due of this]

Answer 2

Adhesiveness

Question 3

Tendency to clump together.

[platelet are difficult to count due of this]

Answer 3

Aggregation

Question 4

Normal platelet size ranges from:

Answer 4

2 - 4 µm

Question 5

The primary function of platelets is:

Answer 5

Blood coagulation

Question 6

The normal platelet count range is:

Answer 6

150, 000 - 400, 000/ uL

Question 7

Whole blood is diluted with REES - ECKER DILUTING FLUID which makes platelets readily visible under the bright-field microscope.

Answer 7

Principle of Direct Platelet count

Question 8

Diluting fluid commonly used in the direct method.

Answer 8

Rees - Ecker solution

Question 9

Anticoagulant of choice for platelet counts is:

Answer 9

EDTA

Question 10

The reference MANUAL PLATELET COUNT method.

Answer 10

Brecher - Cronkite

Question 11

Brecher-Cronkite method uses:

[microscope]

Answer 11

Phase contrast microscope

Question 12

Dilution factor for direct platelet count.

Answer 12

200

Question 13

Platelets are counted in what area of the hemocytometer.

Answer 13

Central large square

Question 14

Red (large square)

[are]

Answer 14

1mm²

Question 15

Green (WBC square)

[area]

Answer 15

0.0625 mm²

Question 16

Brecher - Cronkite Method

[diluting fluid]

Answer 16

1% ammonium oxalate

Question 17

Yellow (RBC square)

[area]

Answer 17

0.04 mm²

Question 18

Blue (smaller RBC square)

[area]

Answer 18

0. 0025 mm²

Question 19

If low counts: Used WBC pipet

[dilution]

Answer 19

1: 20

Question 20

If low counts: Used RBC pipet

[dilution]

Answer 20

1: 100

Question 21

Prevents platelet clumping.

[tocantin’s method]

Answer 21

Neutral formalin

Question 22

Depth of the counting chamber.

Answer 22

0.10 mm

Question 23

Prevents platelet clumping

Answer 23

Neutral formalin

Question 24

[3] Important parameters fo calculating the platelet counts:

Answer 24

1. average number of platelets per square millimeter
2. dilution factor
3. volume of diluted blood counted.

Question 25

Platelet counts below normal indicate:

Answer 25

Thrombocytopenia

Question 26

Platelet count above normal indicate:

Answer 26

Thrombocytosis

Question 27

To allow platelets to settle, hematocytometer is kept covered for?

Answer 27

10 - 15 minutes

Question 28

Platelet counts from both chambers should differ by no more than:

Answer 28

10%

Question 29

BACTERIA and DEBRIS can be mistaken for platelets because they are?

Answer 29

Refractile

Question 30

Platelet aggregation in plasma.

Answer 30

Platelet satellitosis

Question 31

[2] Equipment used: [brecher - cronkite method]

Answer 31

1. Hematocytometer 2. Thoma pipet

Question 32

Microscope: [brecher - cronkite method]

Answer 32

Phase contrast microscope

Question 33

Diluting fluid: [brecher - cronkite method]

Answer 33

1% ammonium oxalate

Question 34

Microscope: [tocantin's method]

Answer 34

Light microscope

Question 35

Diluting fluid: [tocantin's method]

Answer 35

Rees and Ecker

Question 36

[7] Methods for Direct Platelet Count:

Answer 36

1. Brecher - Cronkite 2. Tocantin's 3. Guy and Leake's 4. Nygard's 5. Walker and Sweeney's 6. Van allens 7. Unopette (calibrated)

Question 37

If 5 RBC squares are counted area should be

Answer 37

0.20mm²

Question 38

If 25 RBC squares (central large square) are counted area should be

Answer 38

1 mm²

Question 39

[4] Platelet counts BELOW NORMAL indicate thrombocytopenia and are found associated with: [APAI]

Answer 39

1. Aplastic anemia 2. Pernicious anemia 3. Acute leukemia 4. Idiopathic thrombocytopenia purpura

Question 40

[4] Platelet count ABOVE NORMAL indicate thrombocytosis and are found associated with: [PHCA]

Answer 40

1. Polycythemia vera 2. Hemolytic anemia 3. Chronic Myeloproliferative Disorders 4. After splenectomy