Value of micro-proteinuria in combination with ultrasonography of the left renal vein in the diagnosis of orthostatic proteinuria

Background: This study aimed to evaluate the clinical value of micro-proteinuria in combination with ultrasonography of the left renal vein (LRV) in the diagnosis of orthostatic proteinuria (OP). Methods: The patients with suspected OP received West test, upright lordotic position test, Robinson test, ultrasonography of the LRV, and detection of morning urine micro-proteinuria and micro-proteinuria after activity. The sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV and NPV), positive and negative likelihood ratios (PLR and NLR) and Youden’s index (YI) for micro-proteinuria, ultrasonography of the LRV and both of them in the diagnosis of OP were analyzed. Results: From January 2013 to January 2018, 75 patients (M/F: 38/37) were recruited. Sixty patients were diagnosed with OP (M/F: 29/31, median age at onset: 10.6±2.80 years); 15 patients had no OP (M/F: 9/6, median age at onset: 10.9±3.25 years); the LRV entrapment, urine Alb/Cr, IgG/Cr, and NAG/Cr after activity were significantly different between OP group and non-OP group (Z=–3.55, –4.10, –4.01, –3.04, P Conclusions: The micro-proteinuria in combination of ultrasonography of the LRV is helpful for the preliminary screening of OP in patients with suspected OP.