18 Questions
Which of the following is a purplish-red pinpoint hemorrhagic spot in the skin caused by loss of capillary ability to withstand normal blood pressure and trauma?
Petechiae
What is the term for the form of purpura in which blood escapes into large areas of skin and mucous membranes, but not into deep tissues?
Ecchymosis
What is the term for leakage of blood into joint cavities?
Hemarthrosis
Which disorder is characterized by deficiency in GP Ib/IX/V complex, lack of adhesion to VWF, and abnormal response to thrombin?
Bernard Soulier Syndrome
Which disorder is characterized by a deficiency in GPIIb/IIIa and abnormal in vitro clot retraction with normal platelet count?
Glanzmann Thrombasthenia
What mutation is associated with Wiskott-Aldrich Syndrome?
Mutation in WASp gene
Which syndrome is characterized by a deficiency of alpha granules and mutant NBEAL2 gene?
Gray-Platelet syndrome
What is the hallmark of myeloproliferative disorders associated with thrombocytosis?
Elevation in platelet count
'Thrombocytosis' can have a secondary origin due to:
'Reactive thrombocytosis'
What is the primary function of Catulong, RMT Laboratory Tests for Primary Hemostasis Evaluation?
Evaluating platelet count and function
What is the normal reference range for platelet count in Catulong, RMT Laboratory Tests for Primary Hemostasis Evaluation?
150-450*109/L
Why is platelet count a crucial starting point in evaluating bleeding problems traceable to platelets?
To determine the number of platelets present
What is the significance of knowing the normal platelet estimate of 5-20 platelets per OIF with 200 RBCs?
To assess distribution in an event
What is Platelet Satellitism (Satellotosis) associated with?
Adherence of platelets around neutrophils
What is the correct action when Platelet Satellitism is observed using EDTA?
Repeat the collection using sodium citrate anticoagulant
How can the platelet count be obtained according to the text?
Multiplying the count by a factor of 1:1
What is the term for the form of purpura where blood escapes into large areas of skin and mucous membranes, but not into deep tissues?
Petechiae
What is the term for leakage of blood into joint cavities?
Hemarthrosis
Study Notes
Platelet Count Methods
- Manual plt count (Direct Count): most accurate way of plt count, uses RBC pipet, diluting fluid or unopette
- Tocantins Method: uses Rees-Ecker Diluent with citrate-formaldehyde buffer and brilliant cresyl blue as platelet stain
- Phase-contrast microscopy method (Brecher-Cronkite Method): gold standard, uses 1% ammonium oxalate as diluent and phase microscope to visualize plts
- Unopette method: uses 1% ammonium oxalate
- Indirect Count: Plts are counted in relation to 1000 RBCs
- Stained blood smear Method: includes Dameshek method, Fonio's Method, and Olef's method
- Automated Plt Count: uses Optical Methods (detection of light scatter) and Electrical methods (detection of change in electrical resistance or capacitance)
Platelet Count Interpretation
- Markedly decreased: 0-49k/uL
- Moderately decreased: 50-99k/uL
- Slightly decreased: 100-149k/uL
- Low normal: 150-199k/uL
- NORMAL: 200-400k/uL
- Slightly increased: 401-599k/uL
- Moderately increased: 600-800k/uL
- Markedly increased: >800k/uL
Platelet Function Evaluation
- Evaluates plt count, plt adhesion, plt aggregation
- Reference Range: 150-450109/L, 150,000-450,000/uL, 150-450103/uL
- Platelet number must be sufficient for them to play their supportive role in hemostasis
Platelet Satellitism
- Platelet adhere around the neutrophil forming a ring or satellite effect
- May occur using EDTA
- Correct: Repeat the collection using sodium citrate anticoagulant, obtain plt count by multiplying with factor: 1:1
Thrombocytosis
- Primary Thrombocytosis/Thrombocythemia: a hallmark of myeloproliferative disorders, associated with uncontrolled proliferation of platelets
- Secondary/Reactive Thrombocytosis: underlying disease results in an increase in plt production
Platelet Disorders
- Qualitative: thrombocytopathy, defects in platelet adhesion, platelet aggregation, platelet secretion, membrane phospholipid distribution
- Quantitative: decreased or increased platelet counts
Platelet Adhesion Disorders
- Hereditary: Bernard Soulier Syndrome (Giant Platelet syndrome), deficiency in GP Ib/IX/V complex, lack of adhesion to VWF and abnormal response to thrombin
- Acquired: Myeloproliferative, lymphoproliferative disorders, dysproteinemias, antiplatelet antibodies, cardiopulmonary bypass surgery, chronic liver disease, drug-induced membrane modification
Platelet Aggregation Disorders
- Hereditary: Glanzmann Thrombasthenia, deficiency in GPIIb/IIIa, originally described as a bleeding disorder associated with abnormal in vitro clot retraction and a normal platelet count
- Acquired: Acquired Von Willebrand disease, Acquired uremia
Platelet Secretion Disorders
- Gray-Platelet syndrome: Deficiency of alpha granules, Hermansky-Pudlak syndrome, Wiskott-Aldrich syndrome, Chediak-Higashi syndrome, TAR syndrome
Platelet Reference Range
- 150-450*109/L
- 150,000-450,000/uL
- 150-450*103/uL
Explore the various methods used for platelet count in hematology, including manual direct counts like Tocantins Method and Rhese-Ecker Diluent, as well as indirect counts. Learn about the Brecher-Cronkite Method, which is considered the gold standard in platelet counting.
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