Fig. 1From: Tubulointerstitial nephritis in primary Sjögren syndrome: clinical manifestations and response to treatmentDemonstrates distal and proximal tubular dysfunction. Panel a shows urinary acidification tests. Baseline and nadir urine pH values are shown. The dotted line represents the threshold urine pH of 5.3 that determines normal urinary acidification. Panel b shows urinary RBP/creatinine ratio. The dotted line shows the upper limit of normal (32 μg/mmol)Back to article page