Renal biopsy is the gold standard and definitive test of establishing  the diagnosis of AIN, however it is not needed  in all patients and often considered to make a definitive diagnosis for patients who do not improve following withdrawal of offensive agent or in the presence of doubtful findings.
Interstitial nephritis diagnostic study of choice
Lupus nephritis diagnostic study of choice
Lupus nephritis other diagnostic studies
Membranous glomerulonephritis diagnostic study of choice
Rapidly progressive glomerulonephritis diagnostic study of choice
Membranoproliferative glomerulonephritis diagnostic study of choice
Renal papillary necrosis other diagnostic studies
Membranous glomerulonephritis other diagnostic studies