5.1 Lab Ealuation of Primary Hemostasis Flashcards by Miguel Acosta

Q

On the average, if platelet cpunt is normal, there is at least 1 platelet in _______ RBCs or approx. ______ platelets per OIF

A

10-30

8-20

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Q

Specimen for enumeration of platelet?

A

Venous blood is preferred (EDTA)

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Q

Review of peripheral blood smear is advantageous in some points in detecting causes of low counts but it is not the preferred method for routine plt counts such as

artificial due to clumping
clotted specimen
Giant platelets

T or F

A

T

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Q

Due to platelets clumps: In the machine this may cause:

Falsely ______ Platelet ct
Falsely ______ WBC ct

A

Decrease

Increase

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Q

If giant platelet is seen, Manual count is done

T or F

A

T

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Q

Manual platelet Count:
- Direct Method

Preferred method of microscopy

A

Phase contrast microscopy

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Q

Diluting fluid in phase-contrast microscopy?

A

Brecher-Cronkite method (1% ammonium oxalate

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Q

Manual platelet Count:
- Direct Method
- Lightmicroscope

What is the method and diluting fluid?

A

Rees-Exker method: Citrate-formaldehyde buffer with Brilliant Cresyl Blue

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Q

In light microscope, platelets appear refractile and bluish with BCB

T or F

A

T

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Q

In direct method: Platelets are counted in central small squares of Neubauer chamber

T or F

A

T

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Q

Indirect method:

Platelets estimation in peripheral smear using what Field?

A

OIO

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Q

Fator used in Indirect method?

A

20,000

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Q

In Indirect method:

Normally,________/ OIF are seen in healthy indiv.

A

8-20

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Q

Automated Platelet count
- Detect electrical resistance when particles stream through an aperture tube

A

Electrical impedance

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Q

Direct method uses Counting chamber
Indirect Method uses Blood smear

T or F

A

T

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Q

Indirect method is only use to verfy the analyzer

T or F

A

T

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Q

Automated Platelet count
- Particles that are in the range of 2-20 fL are counted as platelets

T or F

A

T

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Q

MPV is between 8-10 fL

T or F

A

T

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Q

Automated Platelet count:

Hemolysis

a. Spurious increase
b. Spurious decrease

A

a

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Q

Automated Platelet count:

Clotting

a. Spurious increase
b. Spurious decrease

A

b

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Q

Automated Platelet count:

Microsytic RBCs

a. Spurious increase
b. Spurious decrease

A

a

Q

Automated Platelet count:

Red cell inclusions

a. Spurious increase
b. Spurious decrease

A

a

Q

Automated Platelet count:

Giant platelets

a. Spurious increase
b. Spurious decrease

A

b

Q

Automated Platelet count:

Clumping, agglutinins

a. Spurious increase
b. Spurious decrease

A

b

Automated Platelet count: RBC and WBC fragment a. Spurious increase b. Spurious decrease

a

Automated Platelet count: Platelet satellitosis a. Spurious increase b. Spurious decrease

b

Resolution for platelet satellitosis?

Change anticoag to citrate

Time it takes for a standard wound t stop bleeding

Bleeding time

Bleeding time evaluates All aspect of: - Platelet count - Platelet function - Blood vessel integrity Which of it does not belong

None

Global test for adequacy of primary hemostasis

Bleeding time

Bleeding time first described by ______ in 1912 and modified by ____in 1941

Duke Ivy

In 1969, Mielke Attemted to standardized the bleeding time by specifying a lancet that used a template to establish incision depth and applying a BP cuff inflated to 40 mmHG to upper arm T or F

T

Standardized cut is made in ______ surface

volar

Blot blood every ____ seconds till it stops

30

Ref method for Bleeding time?

2-9 mins

Process by which the volume of of a formed clot is reduced through contraction of the intracellular actin-myosin cytoskeleton of activated platelets

Clot retraction test

When Blood coagulation is complete, clot normally retracts T or F

T

Normal clot retraction requires: - Normal Platelet cout and function - Normal ATP, calcium, fibrinogen, gb _____

IIb/IIIa

Clot retraction procedure: - Fresh whole blood is placed in a 37C water bath - Inspect at 1,2,4,and 24 hours clot retraction - Normal Value: ______ hours

2 - 4

Marker of capillary fragility ?

Tourniquet test

Tourniquet test is also known as

Rumpel-leede test

Can be used as a triage tool to differential patients with acute gastroenteritis, from those with dengue

Rumpel-Leede test

Procedure for Tourniquet test: - Take patient's Blood pressure and record it - Inflate the cuff at _______mmHg to a point __way between SBP and DBP and maintain for 5 minutes - Reduce and wait 2 minutes - COunt petechiae below ________ fossa - A positive test is ____ or more petechiae per 1 square inch

85 Mid Antecubital 10

Decrease platelet count = __________ Petechiae

Increased

Platelet Aggregometry: Anticoagulant?

Sodium Citrate

Platelet Aggregometry: Specimen ?

Plt-rich plasma or whole blood

Platelet Aggregometry: Reagent?

Agonist

This are substances that induce aggregation

Agonist

Platelet Aggregometry: Instrument: Light-transmittance aggregometer Principle: Change in ____________

Optical density

Platelet Aggregometry: Result: __% platelet aggregation is considered lower limit or normal

40

Response to Epinephrine, ADP, Collagen: - Normal Agg Response to Ristocetin: Defective Agg a. Bernard-Soulier syndrome b. vW Disease c. Glanzmann's thrombastenia

a b

Response to Epinephrine, ADP, Collagen: - Defective Agg Response to Ristocetin: Normal Agg a. Bernard-Soulier syndrome b. vW Disease c. Glanzmann's thrombastenia

c