5.1 Lab Ealuation of Primary Hemostasis Flashcards
On the average, if platelet cpunt is normal, there is at least 1 platelet in _______ RBCs or approx. ______ platelets per OIF
10-30
8-20
Specimen for enumeration of platelet?
Venous blood is preferred (EDTA)
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
T
Due to platelets clumps: In the machine this may cause:
Falsely ______ Platelet ct
Falsely ______ WBC ct
Decrease
Increase
If giant platelet is seen, Manual count is done
T or F
T
Manual platelet Count:
- Direct Method
Preferred method of microscopy
Phase contrast microscopy
Diluting fluid in phase-contrast microscopy?
Brecher-Cronkite method (1% ammonium oxalate
Manual platelet Count:
- Direct Method
- Lightmicroscope
What is the method and diluting fluid?
Rees-Exker method: Citrate-formaldehyde buffer with Brilliant Cresyl Blue
In light microscope, platelets appear refractile and bluish with BCB
T or F
T
In direct method: Platelets are counted in central small squares of Neubauer chamber
T or F
T
Indirect method:
Platelets estimation in peripheral smear using what Field?
OIO
Fator used in Indirect method?
20,000
In Indirect method:
Normally,________/ OIF are seen in healthy indiv.
8-20
Automated Platelet count
- Detect electrical resistance when particles stream through an aperture tube
Electrical impedance
Direct method uses Counting chamber
Indirect Method uses Blood smear
T or F
T
Indirect method is only use to verfy the analyzer
T or F
T
Automated Platelet count
- Particles that are in the range of 2-20 fL are counted as platelets
T or F
T
MPV is between 8-10 fL
T or F
T
Automated Platelet count:
Hemolysis
a. Spurious increase
b. Spurious decrease
a
Automated Platelet count:
Clotting
a. Spurious increase
b. Spurious decrease
b
Automated Platelet count:
Microsytic RBCs
a. Spurious increase
b. Spurious decrease
a
Automated Platelet count:
Red cell inclusions
a. Spurious increase
b. Spurious decrease
a
Automated Platelet count:
Giant platelets
a. Spurious increase
b. Spurious decrease
b
Automated Platelet count:
Clumping, agglutinins
a. Spurious increase
b. Spurious decrease
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
