P1 Laboratory Flashcards
Microscope used in platelet count
Phase-contrast microscope
Anticoagulant used in platelet count
EDTA
WB in platelet count is diluted with and give the reason
1% ammonium oxalate
To lyse non-nucleated erythrocytes
Count platelets in
25 squares in the central large square
In platelet count:
After charging the fluid to the hematocytometer, place in a petri dish with cotton ball for 10 minutes to:
- provides a moist chamber to prevent evaporation of the solution
- allowing time for platelets to settle
Platelet count formula
Platelets = # of cells counted x DCF x VCF
Platelet count:
Dilute fluid:
Draw blood:
Dilute again:
Dilute fluid: 0.5 mark
Draw blood: 1 mark
Dilute again: 11 mark
Used to evaluate the vascular factor and the function of platelets and blood vessels
Bleeding time - DUKE
Used for differential diagnosis for hemorrhagic diseases
DUKE
Fingertip
BLEEDING TIME DUKE
Normal range for Duke
2-4 minutes
Interval of 30 seconds
Involves the determination of increased blood pressure
Ivy’s method
Combined measure of capillary function, platelet numbers and the ability of platelets to the vessel walls and to each to form a plug
Ivy’s method
More sensitive and often gives abnormal result
Ivy’s method
Ivy’s method is require to have
Two incisions/punctures at the volar surface of the forearm below the anti cubital fossa
Incisions: 5-10 cm apart
15 seconds interval
Normal range for Ivy’s method
NR: 1-7 minutes
Var. 1-6 minutes
> 10 minutes = significant
Are minute hemorrhage under the skin and appear as small bruises
Petechiae
Positive for tourniquet test is found in:
Thrombocytopenia
Decreased fibrinogen
Vascular purpura
Give the possible results for Capillary Fragility Test (Tourniquet test- Rumple Leede Method)
1+ few on the anterior part of the forearm
2+ many on the anterior part of the forearm
3+ multiple over the whole arm and back of the hand
4+ confluent on the arm and back of the hand
Normal clot retraction requires a
Normal number of functioning platelets
Calcium
ATP
Normal interaction of plts with fibrinogen and fibrin
An abnormal clot retraction time is found in
Glanzmann thrombasthenia
Thrombocytopenia
Clot retraction (Macfarlane Method)
The formed clot will be small and there will be increase amount of red cells expressed from the clot. (RBC fallout)
Dysfibrinogenemia and Hypofibrinogenemia
Clot retraction (Macfarlane Method)
In _______, the form clot will appear small and ragged, and there will be increased RBC fallout
Disseminated Intravascular Coagulation
Clot retraction begins within _____ after the blood clotted
30 seconds
Factors that affect clot retraction
Fibrinogen
Platelets
Presence of WBC and RBC
Temperature
Thrombin
Computation for clot retraction
Vol. of serum
Clot retraction = ______________ x 100
Vol. of whole blood
NV for clot retraction
NV: 48-64%
Ave: 55%
