Week 10 Flashcards

Question

Diagnosis of DIC

Answer 1

Type of MAHA -thrombocytopenia -shistocytes on PBS prolonged PT and PTT increased D dimer fibrinogen is decreased because fibrinolysis via plasmin is occuring

Answer 2

Negative D dimer means its NOT DIC, PE or DVT -Normal is <0.5 mg/L - in DIC levels are 10000 - 20000 ng/L or 10mg/L in PE or DVT they are a bit lower

Answer 3

-latex fixation slide test (Qualitative) -ELISA -turbidimetric with decease of transmitted light at 405; change is plotted on a standard curve to establish the concentration if D dimer 1)If D-dimers are present, they will agglutinate the latex particles > Clumps 2)If D-dimer absent, solution remains clear

Answer 4

Deficiencies in: Antithrombin Protein C Free PS TPA Mutations of: Factor V F V Leiden (APCR) Prothrombin G20210A Fibrinogen dysfibrinogenemia Plasminogen PAI-1 (elevation) order a thrombosis panel to narrow down what is causing the issue most common are VENOUS thrombosis AT, PC, PS, APC-R

Answer 5

congenital deficiency -serine protease inhibitor that neutralizes thrombin acquired in prolong heparin therapy, DIC, Liver disease etc most cases are due to reduced production or due to mutations that cause abnormalities in protease binding site or heparin binding site Lab assessment :assays, Clot based and chromogenic AT assay , immunoassay for AT concentration

Answer 6

pt AT binds heparin and is activated AT + HEP bind to reagent FXa chromogenic substrate is added but it will be hydrolyzed by the excess FXa not bound to AP+HEP the color produced is inversely proportional to amount of AT

Answer 7

consists of a reagent made up of latex microbeads coated with monoclonal AB directed at AT the AT in pt plasma binds the beads causing latex agglutination and increases turbidity AT concertation is directly proportional to rate of light ABs change

Answer 8

Fuctional (chromogenic) detects both quantitative (amount present) and qualitative (ability to bind protease) AT deficiencies Immunoassay Detects only quantitative AT (amount present) DOESNT TEST FOR FUNCTIONALILITY

Answer 9

Thrombin binds Thrombomodulin which activates Protein C (APC). APC binds free Protein S to stabilize APC-S complex. This complex will go inactivate FVa and FVIIIa Therefore, without Protein C or Protein S, NO inhibition of FVa and FVIIIa, so clotting continues Protein C def and Protein S deficiency - are Vit K dependent (DIC, Liver Disease) No complexes formed no inhibition of FVa or FVIIIa do chromogenic or clot based assays enzyme immunoassay

Answer 10

1)Patient Plasma is mixed with Reagent containing Snake Venom (which is activator of Protein C) 2)Second reagent containing colour substance is added 3)APC in patient plasma will hydrolyze the substrate and create colour Intensity of color is proportional to the activity of Protein C

Answer 11

1)Patent plasma is mixed with Protein C-depleted Normal Plasma ---This ensures normal levels of all factors EXCEPT Protein C 2) Reagent containing snake venom and APTT reagent is added 3) Time to clot is measured Prolongation is proportional to plasma protein C activity (because APC will prolong PTT) APC prolongs APTT

Answer 12

both can affect molecule’s serine protease site (site which binds to FVIIIa and FVa) ****listen

Answer 13

Uses ELISA method – Quantitative and Qualitative -Plate coated with monoclonal Ab directed to Pro C. These monoclonal Ab are used to capture patient’s plasma Pro C -Add an enzyme linked monoclonal antibody (also directed to Pro C) -Add a substrate that changes colour when in contact with that enzyme -Concentration of Pro C is measured by colour development -Assay determines if low functional activity is due to non-functional Pro C (Qualitative) or if there is a quantitative deficiency (Quantitative – normal levels, dysfunctional protein)

Answer 14

Pt plasma + protein S depleted normal plasma +reagent (APC, venom, and PTT) time to clot is measured prolonged = high protein S- proportional Immunoassay - similar to Prc assay for qualitative and quantitative

Answer 15

Activated Protein C Resistance (APC-R) FVa is usually inactivated by APC-Protein S complex , in FVL is there is a mutation on FV molecule Maintains normal co factor ability so coagulation is normal arginine is the site of APC/PS cleavage Va not inactivated!!! > Remains active No reduction in prothrombinase production Continued clotting *****

Answer 16

-suspected based on history PT and PTT is normal screen with APC-R assay pt plasma+ FV deficient plasma (all factors but V ) that way you are assessing only the presence of Fv in pt plasma Two aliquots both contain APTT reagent + FV-depleted normal plasma + Patient plasma First aliquot: 1) Add CaCl 2)Measure time to clot Second aliquot 1)Add CaCl and APC. 2)Measure time to clot APC should inactivate patient’s FVa and prolong APTT –Second aliquot should be prolonged by AT LEAST 1.8x of the first aliquot If person is APC-Resistant (aka has FVL) > there would be normal clotting bc FV is not inactivated (Fv L mutation confirmed by molecular genetics) determine zygosity as homozygous state is high risk LAC interferes with APC-R so go directly to genetics

Answer 17

prothrombin mutation FII G to A mutation increased risk of DVT increased Prothrombin level = more thrombin -molecular genetics to diagnose

Answer 18

-functional or structural abnormality of the fibrinogen molecule -Abnormalities in structure results in resistance to plasmin -Plasmin cant recognize cleaving site so the clot won’t be able to be digested -This means clotting will continue Test - Fibrinogen concentration or Thrombin Time (TT) Assay Decreased Fibrinogen levels Abnormal TT (prolonged) bc abnormal structure makes it so there’s issues with cleaving fibrinogen to fibrin

Answer 19

Without plasminogen, patient is unable to breakdown clots Use of thrombolytic therapy (e.g Recombinant TPA) useless without plasminogen Chromogenic Substrate Assay can be used to measure Plasminogen levels 1)Patient’s plasma is mixed with Reagent containing streptokinase (plasminogen activator) 2)Patient’s plasminogen will be converted to plasmin 3)Plasmin will react with chromogenic substrate to release colour Colour intensity will be proportional to the concentration of plasminogen in patient

Answer 20

deficiency associated with Myocardial Infarction (MI), stroke & DVT -Without TPA, plasminogen cannot be converted - no clot breakdown Chromogenic Substrate Assay to measure TPA activity: 1)Known constant conc of Plasminogen is added to patient plasma 2)Patient’s TPA will convert plasminogen to plasmin 3)Plasmin will react with chromogenic substrate Intensity of colour substrate is proportional to TPA activity

Answer 21

Deficiency associated with mild bleeding INCREASED PAI-1 = thrombosis, primary inhibitor of fibrinolysis – increased levels stops TPA from activating plasminogen – clots don’t get broken down PAI-1 overproduction is measured using indirect approach: 1)Patient plasma is mixed with a fixed amount of reagent and TPA in excess 2)Patient’s PAI-1 will inactivate reagent TPA. 3)The residual TPA that hasn’t been inactivated will activate reagent plasminogen to plasmin. This will react with chromogenic substrate Colour intensity is INVERSELY proportional to patient’s PAI-1 activity

Answer 22

involved in activating plasminogen , if there is a deficiency then fibrinolytic activity is reduced FXII deficiency doesn't always result in bleeding disorders it can be bypassed as a contact factor by direct activation of FXI thrombin

Answer 23

inhibits the Extrinsic Tenase complex TFPI binds directly and inhibits the Xa & TF–FVIIa complex therefore inhibiting continued activation of FXa Low levels of TFPI are a risk factor for clotting disorders Allows for continued FXa activity