Diagnosis of nephritis in cancer patients typically involves a combination of clinical evaluation, laboratory tests, and imaging studies. Blood tests can reveal elevated levels of creatinine and blood urea nitrogen (BUN), indicating impaired kidney function. Urinalysis may show the presence of blood, protein, or inflammatory cells. Imaging studies such as ultrasound or CT scans can help assess structural abnormalities in the kidneys. In some cases, a kidney biopsy may be necessary to confirm the diagnosis and identify the underlying cause.