Name one contraindication for using a venous site for IV therapy.

Using a venous site with a history of previous thrombosis is contraindicated for IV therapy because the presence of a clot can significantly complicate or prevent effective access to the vein. If thrombosis has occurred in a particular vein, it may indicate that the vein is not suitable for further use due to the risk of complications such as embolism or impaired circulation. Additionally, reusing a vein previously affected by thrombosis may lead to damage to surrounding tissue or recurrent clot formation, which can increase patient risk and reduce the effectiveness of therapy.

In contrast, while scarring from previous injections may make access more difficult, it does not necessarily contraindicate the use of that site. A patient’s allergy to latex is relevant for equipment selection, but it does not directly relate to the choice of venous site for access. Similarly, active injection of medication can complicate venous access decisions but isn't a strict contraindication for using a site already suitable for IV therapy.