Which tests check for venous disease?

Test names are easy to mix up when two vein conditions sound alike. This page lines up the question about venous disease testing next to the conditions it gets confused with.
The answer, with its source beside it
The publisher my.clevelandclinic.org names these tests. Tests to diagnose venous disease include ankle-brachial index (ABI) and ultrasound.
Where this question splits from its look-alike
Venous disease, varicose veins and venous insufficiency each have their own publisher pages, and a reader can land on the wrong one from a similar name. Matching the test question to the right condition first keeps the answer from drifting.
A test named on one condition's page answers that page's question. It should not be carried over to a neighboring condition without checking that condition's own source.
Pages to read alongside this one
The Cleveland Clinic page on venous disease is the source for the testing answer above. The Cleveland Clinic page on varicose veins covers the look-alike term. For the insufficiency wording, compare the MedlinePlus Medical Encyclopedia entry on venous insufficiency with the Society for Vascular Surgery page on chronic venous insufficiency.
The follow-up question
Naming the tests leads to another question: which of these conditions is each test being used to rule in or out?