10. laboratory evaluation of fibrinolysis
TRANSCRIPT
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
1/14
LaboratoryEvaluation ofFibrinolysisDonna Therese M. Taguinod, RMT, MPH
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
2/14
Laboratory Tests to Evaluate
Fibrinolysis:1. Whole blood clot lysis time
2. Protamine sulfate dilution test
3. Ethanol gelation test
4. Latex FDP test
5. Latex D-Dimer assay
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
3/14
Whole Blood Clot Lysis Time
Whole blood (No Anticoagulant)should remain clotted and should notshow significant lysis for 48 hours at
37°C
Positive in severe fibrinolysis
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
4/14
Euglobulin Lysis Time:
Is used as a screening test forfibrinolytic activity.
The euglobulin fraction of plasma
consists of Fibrinogen, plasminogen,and fibrinolytic activators
The euglobulin fraction is precipitatedwith 1% acetic acid and resuspended
in a borate solution. Euglobulins areclotted by the addition of thrombin (5units/mL). The resulting clot isincubated (37C) and the time of lysis is
obtained.
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
5/14
Euglobulin Lysis Time:
The clot should remain intact for 2-4hours
Interpretation:
Clot lysis in < 2hours is indicative ofabnormal fibrinolytic activity anddecrease in fibrinogen
A prolonged time > 4 hours is
caused by a decrease inplasminogen or activator.
Note: It does not detect FDPs
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
6/14
Protamine Sulfate Dilution Test
When protamine is added in plasma, itdisplaces the secondary (smaller)degradation products from fibrinmonomer and primary (larger) FDP will
polymerize spontaneously(paracoagulation)
Normally, no gel formation
(+) result : gel formation = DIC,pulmonary embolism, thrombolytictherapy
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
7/14
Ethanol Gelation Test
Less sensitive but more specific thanprotamine sulfate
50% solution ethanol will polymerizeany fibrin monomers resulting to gel
formation
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
8/14
Fibrinogen Levels
Quantitated by various methods includingprecipitation, denaturation, turbidimetry or
fibrin clot density method, coagulableproteins assays, immunological assays and
modified thrombin time. NV: 200-400 mg/dL
Decrease in liver disease or consumption offibrinogen owing to accelerating
intravascular clotting. Fibrinogen titer may be useful:
Normal = 1:128 to 1:256
Abnormal =
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
9/14
Latex FDP Assay
Latex particles are coated with antibodies toFSPs.
If significant level of the fragments are in theserum, agglutination will occur.
DIC
Pulmonary embolism
DVT (Deep vein Thrombosis)
Myocardial infarctionPre-eclampsia
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
10/14
Latex D-dimer Assay:
Measures specific cross-linked D-dimerfragments from degradation of stabilizedfibrin clots by plasmin.
D-dimers are evidence of intravascularfibrin formation.
Monoclonal antibodies to D-dimers areattached to latex particles causing
agglutination if D-dimers are present Specimen of choice: fresh citrated blood
Useful in the diagnosis of DIC
NV:
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
11/14
Plasminogen Assay:
Chromogenic or fluorogenic substrateallow functional quantitation ofplasminogen.
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
12/14
Fibrinopeptides A or B Assay:
Fibrinogen fragments can bemeasured by radio-immunoassay.
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
13/14
Protein C (PC) and Protein – S
(PS) and AT III assaysCan all be measured for a degree of
activity with chromogenic assays or
with immunoassays to measure theconcentration of the molecule (i.eantigen).
-
8/19/2019 10. Laboratory Evaluation of Fibrinolysis
14/14
Activated Protein C Resistance
(APCR) Is the inability of APC to prolong
clotting tests when added to the APTT.
This phenomenon is characteristic of agenetic thrombotic disorder known asfactor V Leiden.