UAMS Hematology Exam 6 - part 2

What is the calculation for INR?

(Patient PT/PT Normal Mean)^ISI

What does aspirin do to platelets?

irreversibly suppresses platelet function. It inhibits thromboxane which is needed for platelet aggregation. The platelets will not aggregate. It is an irreversible reaction.

What are thrombolytic agents? List two.

Clot busters that break up existing clots. Streptokinase or Tissue Plasminogen Activator (TPA) are a couple of them.

What population is most affected by Vitamin K Deficiency?

Preemie newborns

- due to newborns having an immature liver, no GI bacteria, and no vitamins in mother's milk

What other things can cause Vitamin K deficiency?

antibiotics and poor diet

What coagulation test is elevated in Vitamin K Deficiency?

The PT is elevated since Factors II, VII, IX, and X are deficient. Factor VII is most significantly affected.

What are some other names for Inhibitors?

circulating anticoagulants, lupus anticoagulants, and anti-phospholipid antibodies

A defect in which factors will cause thrombosis?

Protein C, Protein S, or ATIII (anti-thrombin III)

Which factor deficiency will cause clotting instead of bleeding?

Factor XII

What factors are found in absorbed plasma?

I, V, VIII, XI, XII (all but the vitamin K factors)

What factors are found in aged serum?

VII, IX, X, XI, XII (contain all but the consumed factors)

Bernard-Soulier Disease is a defect of what?

glycoprotein Ib - GPIb

- it is a defective receptor that binds vWF

Glanzmann's Thrombasthenia is a defect of what?

platelet membrane GPIIb/IIIa

- receptor of binding fibrinogen and vWF

What tests measure the common pathway?

thrombin time and fibrinogen test

- thrombin is factor II, and fibrinogen is factor I

What deficiency does the urea solubility test test for?

Factor XIII

What disease states is the PT elevated in?

vitamin K deficiency, liver disease, and Factor VII deficiency

What therapy does the PT monitor?

Coumadin therapy

What reagent is used for the PT test?

thromboplastin combined with CaCl

What reagent is used in the PTT test?

Actin and CaCl

- actin contains phospholipids and a negatively charged activator

What therapy does the PTT monitor?

heparin therapy

What does the PT, PTT, and TT NOT measure?

platelet function

What has the bleeding time test been replaced with?

platelet count and aggregation studies

What does the Thrombin Time (TCT) test measure?

Measures the time it takes to convert fibrinogen to fibrin.

What is the normal range for TCT, and how do you interpret the results?

Normal range: 15-20 seconds

The longer the TCT, the less fibrinogen is present

What does the fibrinogen test measure?

measures the amount of fibrinogen

What is the normal range for Fibrinogen, and how do you interpret the results?

Normal range: 220-498 mg/dL

The time is takes for detection of a clot is inversely proportional to the amount of fibrinogen.

What is the normal range for D-Dimer?

110-240 ng/dL

A patient with a Hct of >55% has a coag tube drawn on them. No correction is made to the anticoagulant to blood ratio. What will the coagulation results look like?

Causes falsely prolonged results. The decrease in plasma volume relative to whole blood unacceptably raises the anticoagulant-to-plasma ratio.

What happens to coag results if there is a traumatic phlebotomy collection?

Tissue factor (factor III) is activated which falsely decreases the coag results.

What happens to coag results if there is prolonged tourniquet use?

There will be an increase in vWF and Factor VIII which will cause blood stasis and falsely decrease clot based assays.

What happens to coag results if there is a short draw?

increases the concentration of anticoagulant which falsely increases coag results.

What does a fibrometer do?

mechanically searches for clots. If not clots, then sample is most likely lipemia. PT and PTT will be falsely elevated.

Which test is abnormal in factor XIII deficiency?

urea solubility

Why must blue tops be centrifuged for a specified time and speed?

to get platelets out of the plasma

what is the action of thrombin?

cleaves A and B peptides from fibrinogen

If PT, PTT, PLT count are all normal and BT (bleeding time) is increased, what is the problem?

qualitative platelet or vascular disorder

what is the major activator in the fibrinolytic system?

TPA (tissue plasminogen activator)

Which substance starts the clotting process?

exposed collagen

At what platelet count could one have a spontaneous bleed?

<10,000/uL

what is the principle of the FSP/D-dimer test?

antibodies to FSP are attached to latex particles

how do you select platelet satellites?

examine platelet smear

What is the cause of the highest number of serious health threats?

arterial thrombosis

If factor VIII assay had a value of 55% activity, would the patient have bleeding?

no

what is the function of the kinin system?

Vasoactivity, inflammation, activates intrinsic system

What will the PT and PTT results look like if: Blood clot in leg with no treatment?

normal

What will the PT and PTT results look like if: ITP?

normal

What will the PT and PTT results look like if: DIC?

abnormal - elevated

What will the PT and PTT results look like if: Heparin therapy?

increased

What will the PT and PTT results look like if: Hemophiliac carrier?

normal

What will the PT and PTT results look like if: Child scheduled for out-patient surgery?

normal

What will the PT and PTT results look like if: Bleeding time after aspirin ingestion?

increased