Author Question: A D-dimer test is performed in a patient in whom a pulmonary embolism is suspected. The value comes ... (Read 38 times)

karlynnae · **on:** Jul 16, 2018

A D-dimer test is performed in a patient in whom a pulmonary embolism is suspected. The value comes back at 379 mg/L. What does this suggest?

a. Almost completely establishes the pres-ence of pulmonary embolism.
b. Almost completely rules out pulmonary embolism.
c. Establishes roughly a 50/50 chance of pulmonary embolism.
d. Is indeterminate but highly suggestive of pulmonary embolism.

Question 2

How does impedance plethysmography determine the presence or absence of deep vein throm-bosis?

a. Notes resistance to electrical current asso-ciated with blood flow.
b. Radioactive isotopes target clots and show hot on gamma cameras.
c. Uses ultrasonic waves to delineate the presence of clot or clots.
d. Uses radiographic technique to spot the clots.

lou · **Reply #1 on:** Jul 16, 2018

Answer to Question 1

ANS: B
The specificity D-dimer enzyme-linked immunosorbent assay (ELISA) can exclude all but 5 to 10 of patients with acute pulmonary embolism, so this test has been used as an important early assessment. The specificity of the test is only 39, but a value less than 500 mg/L has been shown to rule out venous thromboembolic disease in 98 of patients.

Answer to Question 2

ANS: A
Impedance plethysmography, a noninvasive method, measures electrical impedance to blood flow, which changes with inflation and deflation of a lower-extremity cuff.