Hi welcome to health care magic... Here physical examination should be done first.... Peripheral vascular disease, varicocele, Deep vein thrombosis like cause has to be ruled out.... CBC , colour Doppler like investigation done for initial work up... If needed and thrombus suspected than d dimer can be done for that.... For thrombosis anticoagulant medication needed..... If needed liver profile, kidney profile, protein level can be checked According to cause further treatment can be given... Take care Advise : physician consultation for examination and further work up....