HEMA COAGULATION TEST P2 Flashcards
(71 cards)
Principle: The coagulation time of the whole blood is the length of time required for a measured amount
of blood to clot under certain specified conditions.
LEE AND WHITE METHOD
The Calcium in whole blood is bound by Na citrate thus preventing coagulation. Tissue thromboplastin, to which Ca has been added, is mixed with the plasma, and the clotting time is noted. Factor VII reacts with the tissue factor in the presence of Ca ions to activate factor X.
PROTHROMBIN TIME
PROTHROMBIN TIME NV
10 TO 12 SECS
The Ca in whole blood is bound by the Na citrate anticoagulant to prevent coagulation. The plasma, after centrifugation, contains all intrinsic coagulation factors except Ca and platelets. Ca, a phospholipid substitute for platelets and an activator are added to the plasma. The time required for the plasma to
clot is the _______.
ACTIVATED PARTIAL THROMBOPLASTIN TIME
ACTIVATED PARTIAL THROMBOPLASTIN TIME NV
25-35 SECS
Calcium chloride is added to platelet poor
plasma and the clotting time is determined.
PLASMA RECALCIFICATION TIME
PLASMA RECALCIFICATION TIME NV
90 TO 150 SECS
PLASMA RECALCIFICATION TIME MODIFICATION: ACTIVATED RECALCIFICATION TIME
0.1 ml platelet rich plasma + 0.1 ml of 0.025 M CaCl2 and 0.1 mL of 1% Celite as an activator
ACTIVATED RECALCIFICATION TIME NV
LESS THAN 50 SECS
Principle: _____________ is a thromboplastin like substance that activates factor X. When this reagent is added to plasma, together with platelets and calcium chloride, the coagulation process is begun at the point of factor X activation with subsequent conversion of prothrombin to thrombin and fibrinogen to fibrin.
STYPEN TIME (RUSSELL’S VIPER VENOM TIME)
When Atroxin (reptilase) is added to plasma, it acts by releasing fibrinopeptide A from the fibrinogen molecule. The resultant monomers polymerize end to end, forming a clot.
REPTILASE TIME
REPTILASE TIME NV
10-15 SECS
A measured amount of thrombin is added to plasma. The length of time for a fibrin clot to form is recorded as the ________.
THROMBIN TIME
THROMBIN TIME NV
10-14 SECS
Principle: Patients with _________ deficiency will have prolonged APTT. If the plasma + APTT reagent mixture is incubated for 10 minutes (instead of the routine for 3-5 minutes) the prolonged APTT will be shortened to normal, or almost normal, if the deficiency is due to _______
PREKALLIKREIN (FLETCHER FACTOR
SCREENING TEST) ; Fletcher factor.
The patient’s plasma is clotted by the addition of CaCl2. Urea (5M) is added to the clot. If ________ is absent in the patient’s plasma, the clot is dissolved in less than 24 hours by the Urea.
FACTOR XIII SCREENING TEST
An excess amount of thrombin is added to a specimen of diluted plasma and the clotting time is noted. The concentration of fibrinogen in the unknown sample is determined by comparing results with clotting times of standard reference plasma dilutions containing known amounts of fibrinogen.
QUANTITATIVE FIBRINOGEN
In QUANTITATIVE FIBRINOGEN, the clotting time of the plasma is inversely proportional to the concentration of __________ in the specimen (the higher the ______, the lower the _________)
fibrinogen ; clotting time/fibrinogen conc
A prothrombin time is performed on ______ deficient substrates containing varying dilutions of the patient’s plasma, which is used to correct the prothrombin time. The amount of correction by the patient’s plasma correlates with its factor activity level and is compared to the results of the prothrombin time performed on varying dilutions of an assayed reference plasma in place of the patients plasma. The _____ content of the patient’s plasma is expressed as the percentage of normal.
FACTOR V (II, VII, X) ASSAY
A dilution of the patient’s plasma is mixed with latex particles coated with monoclonal antibodies to the ______. If fibrin degradation products containing the ______ portion are present, agglutination of the latex particles will occur.
D-DIMER TEST FOR FIBRIN DEGRADATION
Patient and control plasmas are mixed with varying dilutions of _________. Each tube is incubated at room temperature for 30 minutes and then observed for fibrin strand or gel formation. The _________ causes gel formation of fibrin monomers and/ or early fibrin split products when they are present in the plasma.
PROTAMINE SULFATE
During the process of disseminated intravascular coagulation, the level of fibrin monomer in the blood increases. NaOH is added to the plasma to elevate the pH to above 7.70. Ethyl alcohol, added to plasma, will cause precipitation of fibrin monomers which maybe present.
ETHANOL GELATION TEST
Addition of ________ to diluted plasma causes the euglobulin portion of the plasma to precipitate. After removing the supernatant, the euglobulins are dissolved in a buffer solution. _____ is added to clot the euglobulins. The clot is incubated at _____ and the time of complete clot lysis is noted
EUGLOBULIN CLOT LYSIS TIME ; 1% acetic acid ; Thrombin ; 37oC
Patient’s plasma is incubated with platelet rich plasma from a normal control in the presence of heparin. The degree of platelet aggregation observed is measured by an aggregometer and compared to the aggregation obtained in the absence of heparin. If the heparin induced antibody is present, platelet aggregation will occur in the presence of heparin.
HEPARIN ASSOCIATED THROMBOCYTOPENIA
TEST (HATT)
