Your husband has a condition called deep vein thrombosis (DVT). Some of the risk factors for deep vein thrombosis are prolonged immobilization , trauma, cancer etc. I would suggest the following tests to find out if there is an underlying cause for your husband s DVT. They are as follows:CBC, chest x-ray, urinalysis, liver enzymes, and serum electrolytes, BUN, creatinine. If a screening colonoscopy has not been done earlier, a screening colonoscopy is also advised. I also suggest Factor V Leiden (FVL) mutation and prothrombin 20210 (PT 20210) mutation tests . These two tests are often used together to help diagnose the cause of inappropriate blood clot (thrombus) formation, including deep vein thrombosis (DVT) and/or venous thromboembolism (VTE).Testing for Factor V Leiden and PT 20120 mutations is used to help determine if an individual has inherited a disorder associated with blot clots . There are many research projects gathering evidence about veterans exposed to agent orange and their associated disease. Some studies show that people exposed to agent orange are more prone to develop Diabetes mellitus which over the years puts a person at risk for DVT. The medical literature shows that some individuals exposed to agent orange had developed DVT however more evidence is needed and research work is going on at the CDC and other institutes. Best regards.