From the Research
A venogram is not the first-line diagnostic test for detecting blood clots in the arm, and ultrasound is usually the preferred initial diagnostic tool. When diagnosing deep vein thrombosis (DVT), a multifaceted approach is required, including clinical assessment, evaluation of pre-test probability, and objective diagnostic testing 1. The pre-test probability of DVT can be assessed using a clinical decision rule, and if DVT is "unlikely", a D-dimer test can be used to exclude DVT 1. If the D-dimer level is increased, compression ultrasound is recommended 1.
Some key points to consider when diagnosing DVT include:
- Clinical assessment and evaluation of pre-test probability are crucial in determining the need for diagnostic testing 1
- Ultrasound is a less invasive and usually the first-line diagnostic tool for detecting blood clots in the arm 2
- Venograms may still be used when ultrasound results are inconclusive or when more detailed imaging is needed 3
- The test is generally safe but carries small risks, including allergic reaction to the contrast dye, infection at the injection site, or rarely, damage to blood vessels 4
In terms of diagnostic accuracy, color Doppler ultrasound has been shown to have a sensitivity and specificity of 100% in the diagnosis of axillary and subclavian vein thrombosis 4. However, if vein stenosis is included, the sensitivity falls to 89% 4. Overall, ultrasound is a suitable first-line alternative to venography in the diagnosis of axillary and subclavian vein thrombosis.