Answer to Question 1
ANS: D
A D dimer of 800 ng/mL is significantly elevated so that the patient is not normal. D dimers are elevated in DIC, pulmonary embolus, and deep vein thrombosis.
Answer to Question 2
ANS: C
When a patient has a deficiency of antithrombin, heparin may be administered in therapeutic or even higher dosages, but it will not exert an anticoagulant effect in vivo, nor will it be detected by the PTT. This is called heparin resistance.