How does someone have an unknown inherited excessive clotting disorder? if no family has it and routine blood work is good. makes me want testing

By the history: Several percent of folks have at least one genetic mutation that makes them more at risk for deep vein thrombi. Here's why I don't believe in routinely testing everybody. First, nobody really knows what to do with such folks if nothing's happened. Second, most of these are autosomal dominant and these folks tend to have a positive family history. "If you won't use the results, don't do the test."