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