Tubulointerstitial nephritis can be divided into chronic tubulointerstitial nephritis and acute tubulointerstitial nephritis, infectious acute tubulointerstitial nephritis. So, how to examine tubulointerstitial nephritis? The following are the examination methods of tubulointerstitial nephritis. 1, test: patients are 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 glucose, uric acid, potassium, sodium, chloride, calcium, magnesium, phosphorus, creatinine, urea nitrogen Blood tests: blood glucose, 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: routine ultrasound examination of both kidneys, CT examination, intravenous pyelogram or retrograde urography as appropriate, renal nuclear scan, bone marrow aspiration and renal tissue biopsy if necessary. 3. Medical history: history of recent drug use, systemic allergic manifestations, abnormal urinalysis, renal tubular and glomerular function damage. The diagnosis of clinical acute interstitial nephritis is generally considered to be established if the first two of these manifestations are present, plus any one of the last two. 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 way to make a definitive diagnosis. Indications include uncertainty of diagnosis or progression of renal failure.