JAK2 and hyperinsulinemic hypoglycemia, familial, 4: Given the inconclusive nature of the initial workup, further testing is warranted to investigate other potential causes of hypercoagulability, such as prothrombin G20210A mutation, methylenetetrahydrofolate reductase gene mutations, protein S deficiency, JAK2 V617F mutation, and antiphospholipid antibody testing.