8.1 Clot Based Screening tests Flashcards
First laboratory procedure designed to assess coagulation (1913)
Lee and White Whole Blood Coagulation Times
Lee and white Whole Blood Coagulation time was used to screen test of all stages of ________ pathway
Intrinsic
Principle:Length of time required for a measured amount of venous blood to form a solid clot
Lee and white Whole Blood Coagulation time
Measures factors in the EXTRINSIC pathway and COMMON pathway.
Prothrombin time
Measures factors in INTRINSIC pathway and COMMON pathway
Activated Partial Thromboplastin Time (APTT)
Measures VII, III
PT
Choice of test for monitoring warfarin therapy or oral anticoagulants
a. PT
b. APTT
a
Depressed clotting factors? (Affected by Warfarin?
II, VII, IX, X
In depressed clotting factor, whic among is not measured by PT?
Factor IX
First factor to be affected by Warfarin?
VII
Specimen for both PT and APTT?
50 or 100 uL PPP
Aliquot is inubated at 37 C between 3 - 10mins
T or F
T
Reagent for PT?
100 - 200 uL of Thromboplastin
Reference: 12.6 to 14.6
a. PT
b. APTT
a
Ref: 26-38
a. PT
b. APTT
b
In International Normalized Ratio: What is the formula for PT?
( Patient’s PT / PT control ) ISI
Healthy individuals should have INR of: 0.8 to 1.1
If patient is taking warfarin to prevent blood clots, doctors will most likely choose to keep INR between 2.0 and 3.0
T or F
T
higher INR = Higher chances of bleeding
T or F
T
Also known as Clot Busters
Warfarin
Measures: XII, II, HMWK, PK, IX, VIII
APTT
Monitor the effects of unfractionated heparin (UFH); detects Lupus Ac and antifactor-VIII antibody
APTT
Reagent for APTT?
50 or 100 uL of Partial Thromboplastin / Cephalin
0.025 M CaCl2
PT w/ INR: Abnormal
APTT: Abnormal
Problem?
a. Intrinsic
b. Extrinsic
c. Common
c excluding XIII
PT w/ INR: Abnormal
APTT: Normal
Problem?
a. Intrinsic
b. Extrinsic
c. Common
b
PT w/ INR: Normal
APTT: Abnormal
Problem?
a. Intrinsic
b. Extrinsic
c. Common
a
Measures Conversion of Fibrinogen to Fibrin?
Thrombin Time
