Regarding diagnosis of DVT, which statement is most accurate?

• A. D-dimer elevation is always normal in DVT.
• B. Venous angiography is the only screening test.
• C. CT venography is the gold standard.
• D. D-dimer elevated with clot; venous duplex ultrasound is the gold standard screening.

Answer: (D)

DVT diagnosis is best approached by combining a clinical assessment with targeted testing, where the D-dimer and the imaging test work together to confirm or exclude thrombosis. D-dimer reflects fibrin breakdown and tends to be elevated when a clot is forming, but it isn’t specific to DVT and can be raised in many conditions. A normal D-dimer can effectively rule out DVT in patients with low pretest probability, but a positive D-dimer alone doesn’t confirm it.

The most reliable noninvasive way to confirm DVT is venous duplex ultrasound. It directly evaluates the veins for clot by assessing compressibility and blood flow; if the vein cannot be compressed or shows abnormal flow, that supports a DVT diagnosis. This test has high sensitivity and specificity and is the standard imaging test used in current practice.

Other imaging options exist, such as CT venography or venography, but they are less favored due to radiation, contrast use, and invasiveness, respectively. So the statement that D-dimer rises with clot and that venous duplex ultrasound is the gold-standard screening test best captures the practical approach to diagnosing DVT.