Which of the following deficiencies prolongs the PTT but does not ...

[tuffie]

Which of the following deficiencies prolongs the PTT but does not lead to abnormal bleeding?
 
  a. Factor V
  b. Factor VIII
  c. Factor XI
  d. Factor XII

Question 2

Why is it important to monitor patients who are receiving anticoagulant therapy?
 
  a. Drugs are expensive.
  b. Prophylactic and therapeutic dosage ranges are unknown.
  c. Patients commonly abuse these drugs.
  d. Clinical consequences for overdosing or underdosing are significant.

[Kimmy]

Answer to Question 1

ANS: D
A deficiency of factor XII prolongs the PTT. However, patients with this deficiency do not have abnormal bleeding.

Answer to Question 2

ANS: D
The clinical consequences for incorrect dosage of anticoagulant drugs are significant. Overanticoagulation can lead to serious bleeding that may even require a visit to the emergency department. Underanticoagulatio n can lead to further thrombotic events (presumably the reason the patient is on the drug). The prophylactic and therapeutic ranges for the drugs are known and are narrow, which is another reason they must be monitored. Some of the drugs are expensive, but others are not.