Why is the D-dimer test not routinely performed on hospital inpatients suspected of having pul-monary emboli?

a. A high D-dimer only suggests the pres-ence of comorbidities.
b. A low D-dimer is associated with immu-nodepression.
c. It loses sensitivity if numerous blood tests have been performed.
d. The cost is prohibitive.

ANS: A
Inpatients should undergo an imaging study as the initial test for pulmonary emboli because most will already have elevated D-dimer levels due to comorbid conditions.