COAGULATION TESTS Flashcards
the anticoagulant used is..
3.2% sodium citrate
anticoagulants..
Closer osmolality to plasma and produces more ____________ results when patients are treated with ________
accurate activated partial thromboplastin time (APTT) ; heparin therapy
anticoagulants that should not be used
Heparin, edta or oxalate
Tubes are stored best in open containers in an ______
upright position
specimen handling..
_____, changes begin to occur and labile factors such as ____ begin to deteriorate quickly.
In vitro ; VIII
specimen handling..
Pt should be completed within ______
24 hours
specimen handling..
Aptt should be completed within ____
4 hours
specimen handling..
Samples should only be held for a maximum of __ hours at ______ centigrade, if testing cannot be performed immediately
2 ; 4 degrees
specimen handling..
- If testing is not conducted, plasma should be separated from the cells by ______ to produce a _________ (platelet count <10x109/L)
- Done by centrifuging the whole blood specimen for _____ min at _____
centrifugation ; platelet-poor plasma
20 min at 2,500rpm
specimen handling..
-20 degree centigrade for up to _____
-70 degree centigrade for up to _____
2 months ; 6 months
specimen handling..
_______- should not be used, it can prolong clotting time of lupus anticoagulant screening assay.
frost-free freezers
specimen handling..
Frozen specimen should be thawed rapidly at _____ while gently inverted to prevent denaturation of ______
37 deg. Temp ; fibrinogen.
specimen handling..
If thawed sample not tested immediately, sample held for _____ at _____
2 hours at 4 degree cent.
specimen handling…
For lupus anticoagulant, centrifuge at _____ for _____ at ______ and ______ removed and centrifuge again
1,500g ; 15 minutes ; room temp ; plasma
specimen preparation..
_____ PLASMA/_____ SERUM CAN BE USED
Adsorbed ; AGED
specimen preparation..
- PLASMA CAN BE ADSORBED BY __________/_____
- AFTER ADSORPTION, ADSORBED PLASMA CONTAINS FACTORS __________
- AGED SERUM CONTAINS FACTORS ______ (NONANTICOAGLATED WHOLE BLOOD IS ALLOWED TO CLOT;INCUBATED AT ___ DEG. CENT. FOR __ HRS; ______ is added to whole blood
- BARIUM SULFATE/ALUMINUM HYDROXIDE
- I,V,VIII,XI AND XII
- VII,IX,XI AND XII ; 37 ; 3 ; Na citrate
GENERAL SOURCES OF ERROR
= Detergent residues and scratched glassware can produce erroneous results
= Variation in ph, reagent concentration, temperature
Measures the time required to generate thrombin and fibrin polymers via the intrinsic pathway
ACTIVATED PARTIAL THROMBOPLASTIN TIME
In apt, _____ and ______ that substitute for platelet phospholipids are added to blood plasma.
calcium ions ; phospholipids
In APT, the generation of _____ is the end point.
fibrin
Used to identify and quantitate deficiencies in the intrinsic clotting system and to control anticoagulant therapy
ACTIVATED PARTIAL THROMBOPLASTIN TIME
ACTIVATED PARTIAL THROMBOPLASTIN TIME NV:
20-35 sec/28-42 sec; 42-46 sec being marginal
ANTITHROMBIN III: CLOTTING ASSAY METHOD
In the presence of _______, thrombin is neutralized at a rate that is proportional to the _________ concentration
heparin ; antithrombin (AT III)
ANTITHROMBIN III: CLOTTING ASSAY METHOD
Following defibrination, plasma is assayed in a two-stage procedure that utilizes standardized amounts of ______, _____ and ______
heparin, fibrinogen and thrombin
ANTITHROMBIN III: CLOTTING ASSAY METHOD
Resulting time is interpreted using a _______
calibration curve
AT III assay-useful prior to and subsequent to treatment with heparin in cases of ____________
disseminated intravascular coagulation (DIC)
An in vivo measurement of platelet adhesion and aggregation on locally injured vascular subendothelium
STANDARDIZED IVY METHOD
BLEEDING TIME
STANDARDIZED IVY METHOD
BLEEDING TIME…
Estimates integrity of _________
platelet plug
STANDARDIZED IVY METHOD
BLEEDING TIME..
Measures interaction between _______ and ________.
capillaries and platelets
STANDARDIZED IVY METHOD
BLEEDING TIME…
Measures ______ two standardized punctures of the _______ take to stop bleeding
length of time ; ventral forearm
The euglobulin fraction of plasma contains ____,_____ and ____ with the potential for transforming plasminogen to ____
plasminogen, fibrinogen and activators ; plasmin
EUGLOBULIN LYSIS TIME..
Fraction is precipitated with _______ and resuspended in a ________
1% acetic acid ; borate solution
EUGLOBULIN LYSIS TIME..
Screening procedure for _______ activity
fibrinolytic
THROMBO-WELLCOTEST FIBRIN SPLIT PRODUCTS…
Whole blood is added to ______ and ______ enzyme inhibitors
thrombin ; soya bean
THROMBO-WELLCOTEST FIBRIN SPLIT PRODUCTS…
Patients serum is diluted and mixed with ______ coated with ______ products
latex particles ; anti-fibrin split
THROMBO-WELLCOTEST FIBRIN SPLIT PRODUCTS…
agglutination __
+
FIBRINOGEN ASSAY: METHOD CLOTTING ASSAY
Fibrinogen-thrombin _____ ————- _____
factor II ——– fibrin
PROTAMINE SULFATE ASSAY..
Protamine is used to neutralize the effects of _____
heparin
PROTAMINE SULFATE ASSAY..
Excess amount –capable of interfering with ______ activity and _______ generation
factor ix ; thromboplastin
PROTAMINE SULFATE ASSAY..
+ inappropriate presence of ________________
intravascular fibrin monomers
PROTHROMBIN TIME..
The calcium in whole blood is bound by __________, preventing coagulation
Na citrate
PROTHROMBIN TIME…
_______ reacts with the tissue factor-thromboplastin in the presence of calcium ions to activate ______
Factor vii ; factor x
A measure of the intrinsic coagulation mechanism
PLASMA RECALCIFICATION TIME
PLASMA RECALCIFICATION TIME..
A decrease in any of the clotting factors present in the intrinsic system will cause a ______________
prolonged clotting time
PLASMA RECALCIFICATION TIME NV
90-250 sec
STYPVEN TIME, RUSSELL’S VIPER VENOM TIME
Detects deficiency in ___________, __________ and factors ___ and ___
prothrombin time, fibrinogen, v and x
STYPVEN TIME, RUSSELL’S VIPER VENOM TIME
N.V
6-10 sec
STYPVEN TIME. RUSSELL’S VIPER VENOM TIME
Principle:
- Thromboplastin-like substance that activates factor _
- When added to ______, platelets and ca calcium chloride coag process begun at the point of factor x activation with conversion of prothrombin to ______ and fibrinogen to _____.
- x
- plasma ; thrombin ; fibrin
REPTILASE TIME..
Reptilase enzyme found in venom of _________-
bothrops atrox snake
Reptilase enzyme found in venom of bothrops atrox snake
- Converts fibrinogen to fibrin, unaffected by ____
- Test functional fibrinogen when the _____ is prolonged because of heparin
heparin ; thrombin
REPTILASE TIME NV
10-15 sec
REPTILASE TIME PRINCIPLE
- ______ (reptilase) is added to plasma
- It acts by releasing _______ a from fibrinogen molecule.
- Resultant monomers polymerize end-to-end, forming a ____
atroxin ; fibrinopeptide ; clot
Deficiency detected with a modification of the activated partial thromboplastn time
PREKALLIKREIN (FLETCHER FACTOR SCREENING TEST)..
PREKALLIKREIN (FLETCHER FACTOR SCREENING TEST) principle:
- ______ with ______ deficiency will have prolonged apt
- If the plasma + apt reagent mixture is __________, the prolonged apt will be shortened to normal, or almost normal (due to _________)
- Normal clotting occurs with concentrations of _______ and above
- aeg with Fletcher factor
- incubate for 10 min ; fletcher factor
- 1.5 to 2%
FACTOR XIII SCREENING TEST..
____ converts fibrin clot to a more ____ form
Fsf ; stable
FACTOR XIII SCREENING TEST PRINCIPLE:
- aeg’s plasma is clotted by _______
- ______ is added to clot
- If negative- the clot is dissolved in less than ____ by urea
- calcium chloride
- Urea (5m)
- 24 hours
RISTOCETIN COFACTOR ASSAY..
Aeg’s plasma is added to a standardized mixture of _______ and _______ reagents
platelets and ristocetin reagent
RISTOCETIN COFACTOR ASSAY..
Degree of resultant platelet aggregation is measured using ________
aggregometer
HEPARIN (Anti-xa) ASSAY..
Heparin binds with ___________
antithrombin III
HEPARIN (Anti-xa) ASSAY..
_____ method will be used to assay
chromogenic assay
HEPARIN (Anti-xa) ASSAY..
_________ reagent is used
Citrated Plasma
HEPARIN (Anti-xa) ASSAY..
_______ is incubated with measured amount of ________ and ________, substrate is added to the mixture.
aeg plasma ; antitrhombin II ; factor XA.
HEPARIN (Anti-xa) ASSAY..
________ is released and measure __________
Paranitroanilide ; spectroprotometrically