INSTRUMENTATION LABORATORY ASSAYS

activates intrinsic pathway

Use of Plastic/Silicone Coated Glass Tube

9:1

ratio using sodium citrate tube blood anticoagulant

processed after collection

Specimen Processing

within 4 hours

Specimen Processing recommendation if PTT

24 hours

Specimen Processing recommendation if PT

37 deg C

temperature performed at 37 deg

>37

FV and VI -breakdown at temp

cold temp

F VIl and XI - activated at

Activated Partial Thromboplastin Time

screening tests for FXI, X1, Pre-K, HMWK, IX, VIII, X, V, Il and I (Intrinsic Pathway)

Activated Partial Thromboplastin Time

Monitor unfractionated Heparin therapy

1. Platelet Phosphilipid Substitute +Activator (Kaolin/celite/silica/ellagic acid)

2. 0.025M Calcium Chloride

reagents used in activated partial thromboplastin time

Adding phospholipid/activator to citrated poor plasma and incubate to allow contact factor activation. Add Calcium Chloride, measure time required for clot formation.

what is the principle of activated partial thromboplastin time?

Calcium Chloride

what needs to be added in order to measure time required for clot formation?

23-35 seconds

aptt ref range is?

appt

Prolonged:

- Factor Deficiencies (25-30%)

- Acquired circulating inhibitor: Heparin, Lupus Inhibitor and Ab to a factor

falsely prolonged

- Inadequate sample

- large clot in the tube

- contaminated Heparin (IV)

- Hct >50%

- lipemic/icteric sample (optical method)

falsely shortened

- Hemolysis

- small clot

- plasma containing platelets

- Incorrect dilution

- water impurities

- improper storage

Incorrect reagent preparation indicates?

prothrombin time

screening FVII, X, V, Il and I (Extrinsic and Common pathways)

prothrombin time

monitors anticoagulant therapy (Warfarin/Coumadin) Vitamin K Antagonist

Thromboplastin source (TF) + 0.025M Calcium Chloride

reagent used in partial thromboplastin time

Add Thromboplastin reagent + Calcium Chloride to Citrated platelet poor plasma

what is the principle of thromboplastin time?

10-14 seconds

ref range for pt

International Normalized Ratio

standardizing the PT result worldwide

international normalized ratio

not dependent on thromboplastin reagent/instrument used to monitor warfarin/coumarin therapy

2-3 seconds

international normalized ratio ref range is?

international severity index

for thromboplastin reagent, this number is provided by the rgt manufacturer

prothrombin time

Prolonged:

Factor Deficiencies in Extrinsic/Common Pathway

- Inadequate sample

- large clot in the tube

- contaminated Heparin (IV)

- Hct > 50% and lipemic/icteric sample (optical method)

falsely prolonged pt indicates?

small clot in tube

falsely shortened prothrombin time

Reptilase time

occassionaly used to confirm Dysfibrogenemia

Bothrox atrops

reptilase time mimics Thrombin Time tests but it uses (Atroxin)venom from _________ as as reagent

10-15 seconds

reptilase time ref range

Bovine thrombin reagent at 5 National Institutes of Health

(NIH) units/mL cleaves fibrinopeptides A and B from plasma fibrinogen to form a detectable fibrin polymer.

what is thrombin time principle?

15-20 seconds

thrombin time normal values

thrombin time

Prolonged: Decreed Fibrinogen level / Impaired Fibrinogen function

mixing studies

performed when the PT/PTT is prolonged

mixing studies

to differentiate a factor deficiency from a circulating inhibitor

mixing studies

patient's plasma is mixed with normal pooled plasma ans tests are repeated

factor deficiency

shortened mixing studies indicates?

circulating inhibitor

partial/ no correction mixing studies indicates?

fibrinogen assay

quantitative tests for fibrinogen level

thrombin reagent

what reagent is used in fibrinogen assay?

Thrombin+ undiluted patient's plasma, measurement of ThrombinClotting Time is obtained.

what is the principle of fibrinogen assay?

factor assay

use to confirm suspected factor deficiency

factor assay

measures the ability of a patient's plasma to correct the PT/PTT result obtained with plasma known to have a factor deficient.

factor activity percent

factor assay is reported in?

duckert's test

5.0 m urea clot solubility test is also known as?

5.0 um urea clot solubility test

screening test for XIII def

5.0 um urea clot solubility test

prolonged:

Unstable clot that forms in FXI deficiency dissolves in 5.0 M Urea

24 hrs

Normal: Factor XIlla-stabilized clot remains intact in 5.0 M Urea for atleast ______

Stypven Time Test

dilute russel viper venom test is also known as

dilute russel viper venom test

determines factor deficiency in common pathway

dilute viper venom test

sensitive test that used snake venom as reagent to activate

FX

6-10 s

dilute viper venom test normal values are?

venom is neutralized, thus result is prolonged

in Dilute Viper Venom test, the Lupus Inhibitor is present this indicates that?

37 C

whole blood

placed in glass tube containing activator,

determined time it takes to form clot in?

CABG

POCT, omst often use to monitor high-dose heparin therapy during?

fibrin degradation product

latex particles coated with antibody against fibronogen and are mixed with patient's serum

presence of degradation products

RESULT in FDP

(+) macroscopic agglutination particles = ________

DIC and primary fibrinogenolysis

Result:

(+) macroscopic agglutination particles = presence of degradation products

Indication: ??

d-dimer assay

latex particle are coated with antibodies against D-Dimer and presence of cross-linked D-Dimer indicates that a stable fibrin clot has been lysed

Primary Fibrinogenolysis

D-DDIMER ASSAY

Result: DIC, Pulmonary embolism, DVT and DIC w/ secondary fibrinolysis

Normal Result: _______

PALSMINOGEN ASSAY

chromogenic substrate assay mimics the natural enzymatic process whereby plasminogen is converted to active plasmin which cleaves its substrate fibrinogen

Streptokinase (b-hemolytic activator

streptococci) - a plasminogen

reagent used in plasminogen assay

protamine sulfate test

detects presence of fibrin monomers in plasma

formation of coagulation strands / gel-like clot

protamine sulfate test

Abormal result: (+) _____________

Normal: (-) gel formation

whole blood clot lysis time

test for increased fibrinolysis

Normal: Intact clot for approx. 48 hours at 37 deg C

Abnormal: Clot lysis < 48 hours ( excessive fibrinolysis activity)

euglobulin lysis time

screening test to measure fibrinolytic activity

Eugobulin

protein made of plasminogen, plsmin, fibrinogen and plasminogen activator

euglobulin lysis time

Procedure:

The fraction is precipitated w/ 1% acetic acid and resuspended Borate solution. The Suglobulins are clotted by the addition of thrombin. Clot is icubated and the time of lysis is reported.

>1-2 hrs

normal lysis time for euglobulin lysis time

abnormal lysis time for euglobulin lysis time