Urinary Protein Biomarkers and Renal Angina Index for Detection of Renal Dysfunction in Sick Full-Term Neonates

Background: By the help of urinary proteins, the mechanism of kidney damage can be understood and diagnosis of renal dysfunction in sick neonates can be reached. Objective: Usage of specific urinary proteins to assess renal function in ill full term infants with different early disorders. Methods: One hundred full term infants were included in this cross sectional study. They were grouped by Neonatal Therapeutic Intervention Scoring System (NTISS) into 40 healthy infants, 30 infants manifested by clinical signs of moderate disorders of early neonatal period, 19 infants manifested by severe disorders without acute kidney injury (AKI), and 11 infants manifested by severe disorders and AKI. Renal angina index was estimated, albumin/creatinine ratio and the urinary β2-microglobulin (Uβ2-MG) were evaluated. Results: Means (± SD) of urinary β2-microglobulin (Uβ2-MG) values, albumin/creatinine ratio (ACR) and renal angina index were significantly higher in severely sick infants with AKI group IIIB (p-value <0.5 and 0.00, 0.00 respectively). ROC curves were plotted for those three parameters to determine the best cutoff for diagnosis of AKI. Uβ2-MG >8961 ug/L exhibited a sensitivity of 100%, specificity 93.88%, ACR level >144.2 mg/g displayed a sensitivity of 81.82% and specificity of 93.88% and RAI >9 demonstrated a sensitivity of 81.82% and specificity of 87.76%. Conclusions: Cut off value >9 for RAI can predict the development of AKI in full term infants that is accompanied with complex disorders affecting all structural elements of the nephron, assessed by increased concentrations of urinary protein markers of glomerular (albumin/creatinine ratio) and tubular (β2-microglobulin) malfunction.