Conclusions
When we came across a patient who manifested as hematuria or acute kidney injury with a history of anticoagulants usage, we should think of ARN and pay more attention on history collection. Secondly, subacute interstitial nephritis may coexist with ARN. Thirdly, hemoglobin immunohistochemical staining may be helpful to make it clear whether the intra-tubular protein casts came from red blood cells. In addition, for those patients who may have decreased kidney function, anticoagulants dose should be reduced to prevent the occurrence of ARN.