Tubulointerstitial nephritis can be divided into chronic tubulointerstitial nephritis and acute tubulointerstitial nephritis, infectious acute tubulointerstitial nephritis. So, how is tubulointerstitial nephritis diagnosed? The following are the diagnostic methods of tubulointerstitial nephritis. 1, interstitial nephritis examination of the test: the patient was admitted to the hospital for 3 consecutive routine urine examination, and then 2 to 3 times a week, pay attention to the weekly examination of urine protein quantification, disc electrophoresis urine, β2-microglobulin, lysozyme, TH-protein, retinol binding protein, morning urine osmolality, urine pH, 24h urine potassium, sodium, chloride, calcium, magnesium, phosphorus, uric acid, blood sampling for blood sugar, uric acid, potassium, sodium, chloride, calcium, magnesium Phosphorus, creatinine, urea nitrogen, carbon dioxide binding capacity, blood sedimentation, anti-O, anti-nuclear antibody, ds-DNA, SM antibody, blood or urine eosinophils and endogenous creatinine clearance rate. 2, other tests for interstitial nephritis: routine ultrasound of both kidneys, CT, intravenous pyelogram or retrograde urography as appropriate, renal nuclear scan, bone marrow aspiration and renal tissue biopsy if necessary. The typical cases of interstitial nephritis often have a history of recent drug use, systemic allergic manifestations, abnormal urinalysis, tubular and glomerular impairment. The general diagnosis is that if the first two of these manifestations are present, plus any of the last two, the diagnosis of clinical acute interstitial nephritis can be established. However, atypical cases often do not have the second item and must rely on renal puncture pathology to confirm the diagnosis. Renal biopsy is the only method for definitive diagnosis. Indications include uncertainty of diagnosis or progression of renal failure.