Laboratory Evaluation of Primary Hemostasis

Quantitative Platelet Count

Assess the number of platelets

150-400 × 10⁹ /L

Normal Volume of Platelets

Thrombocytopenia

Decrease in Platelets

Thrombocytosis

Increase in Platelets

Brecker Cronkite Method

Reference method for Quantitative Platelet Tests

Phase-Contrast Microscope

What microscope does Brecker Cronkite Method use?

1% ammonium oxalate

Diluting fluid of brecker cronkite method

Hemacytometer and WBC thoma pipettes

Tocantin’s Method uses what tools

1:200

Dilution of WBC thoma pipettes

Simple light microscope

Tocantin’s Method uses what microscope

Reese and Ecker

Diluting Fluid for Tocantin’s Method

• Brilliant Cresyl Blue

• Neutral Formalin

• Sodium Citrate

Alternative diluting fluid for Tocantin’s Method

25

How many RBC squares are counted for Tocantin’s Method

WBC pipette (1:20 dilution)

If low count for Tocantin’s Method, what is used

Brecker Cronkite Method and Tocantin’s Method

What methods are used for Direct Method

Indirect Method

• Used for platelet estimation

• Allows visualization of platelet morphology

Fonio’s and Dameshek Method

Indirect Methods

Fonio’s Method

1 OIO should have 3-10 platelets per 100 RBC

Automated Method

• Optical and electrical methods

• Optical degree of light scattering

Qualitative Platelet Tests

Assess the function of platelets

Capillary Resistance Test

Pressure cuff is used in 100mg/Hg for 5 minutes, count petechiae after 15-30 minutes

Thrombocytopenia

Capillary Resistance Test is correlated with degree of

Few petechiae on the anterior part of forearm

1+ Qualitative Description

0-10

1+ Quantitave Description

Many petechiae on the anterior part of the forearm

2+ Qualitative Description

Multiple petechiae over the anterior and the back of the hand

3+ Qualitative Description

Confluent petechiae over the anterior and the back of the hand

4+ Qualitative Description

10-20

2+ Quantitative Description

20-50

3+ Quantitative Description

>50

4+ Quantitative Description

Glass bead retention dish

Platelet Retention Test is also known as

EDTA/Heparin

Tubes used to collect specimen for Platelet Adhesion Test

Control

1st tube for Platelet Adhesion Test

Platelet Count

2nd Tube for Platelet Adhesion Test

Platelet count; Lower count 75-95%

3rd Tube for Platelet Adhesion Test

• Bernard Soulier

• Glanzmann Thrombasthenia

• vWD

• Chediak-Higashi

• Myeloproliferative Disorders

• Uremia

• Aspirin Administration

Decreased Platelet Retention

• Thrombotic Disorder

• Hyperlipidemia

• Carcinoma

• Oral Contraceptives

• Pregnancy

Increased Platelet Retention

Bleeding Time

Time required for blood to stop bleeding

Congenital platelet problems

Bleeding Time is affected if there are

Infants and Children

Duke’s test is for

Earlobes

Duke’s test is done in

2-8 mins

Normal Value for Duke’s Test

5cm, Antecubital Fossa

Modified Ivy’s Test is done how many centimeters below what part

40-60 mmHg

Modified Ivy’s Test pressure cuff

5mm length and 1mm depth

Modified Simplate Test is done by making a wound incision of

Clot Retraction Test

• Assess function of thrombostenin

• Assess entire platelet function and coagulation

Serum

Is expressed from the clot

• thrombocytopenia

• low and abnormal fibrinogens

• paraproteins

• Glanzmann’s thrombasthenia

Abnormal CRT

Hirshboek Method and Mcfarlane Method

Methods of Clot Retraction Method

Castor Oil

Hirshboek Method utilizes

Dimpling Phenomenon

In Hirshboek Method after 15-45 min check for

Mcfarlane Method

Uses wire loop to check for clot then water bath

1 hour

Macfarlane Method is checked after how many hours

50%

In Mcfarlane Method, blood volume should decrease up to

44-67%

Normal Value for Mcfarlane Method

Platelet Factor III Assay

Platelet Phospholipids provides surface to which clotting factors bind

PPP and PRP

Platelet Factor III Assay needs patient

Pooled PPP, sample, activators, 0.025M CaCl_²

Control for Platelet Factor III Assay

Tissue Thromboplastin Reagent

Activator for Platelet Factor III Assay

Activators

Directly stimulates platelets to produce PF3

Kaolin and Epinephrine

Activators for PF3

Platelet Factor IV and Beta Thromboglobulin Assay

Used as indicator for platelet activation in myocardial infection, diabetes, venous thrombosis

RIA

Platelet Factor IV and Beta Thromboglobulin Assay is measured through

4C

Platelet Factor IV and Beta Thromboglobulin Assay specimen must be refrigerated to what temperature prior to testing

Aggregometer

Platelet Aggregation Test uses an

PRP

Specimen for Platelet Aggregation Test

8 hours

For platelet aggregation test, patient has to fast for atleast how many hours to avoid a lipemic sample

Refrigerator

Specimens for platelet aggregation test must not be placed in a ___ to avoid aggregation

ADP

Specimen for platelet aggregation must not be hemolyzed to avoid the release of

7 days

Platelet Aggregation test should not take aspirin within how many days

6.5 to 8.5

For platelet aggregation test specimen must be in water bath at what pH

• ADP

• Collagen

• Epinephrine

• Thrombin

• Ristocetin

• Arachidonic Acid

Aggregating agents