This test is useful for evaluation of patients with undiagnosed kidney disease. It helps in following the course of therapy or disease progression. It also diagnoses disease caused by immune mechanisms. Biopsy of transplanted kidney is particularly important in determination of acute rejection, infection or recurrent disease. TEM analyzes renal parenchyma at very high magnifications and is critical in diagnosing certain diseases where pathological features are not discernible under light microscopy e.g. Alports disease, Thin Basement membrane disease, Fibrillary glomerulonephritis, Immunotactoid glomerulonephritis, Dense deposit disease etc. It is also useful in renal allografts to diagnose recurrence or de novo development diseases.