Читать книгу Uric Acid in Chronic Kidney Disease - Группа авторов - Страница 13

Humans are adapted to the presence of metabolic waste products, where urate ions are not the exception, and threshold values in men are 1,200 mg/dL, usually higher than that in women. During the fertility timeline, uric acid renal transporters decrease, thereby, producing an imbalance between reabsorption and excretion [3].

Under normal conditions, the kidneys excrete about 70% of total body uric acid production and a smaller proportion is secreted into the intestine and metabolized by gut bacteria in a process termed intestinal uricolysis [1, 2, 4]. In a human urine sample, the reference range of uric acid is typically 620 ± 75.20 mg/dL, which includes the uric acid excretion rate (product of the filtered load) of 0.40 ± 0.09 mg/dL and fractional excretion of urate (FEUA) 7.25 ± 2.98% [1, 2].

FEUA represents the percentage of filtered urate that is excreted in the final urine. It is obtained from urine and plasma samples and calculated as FEUA = C_UA/C_Cr × 100% = ([U_UA × Urine sample volume]/P_UA)/([U_Cr × Urine sample volume]/P_Cr) × 100% = (U_UA × P_Cr)/(P_UA × U_Cr) × 100%. Homeostasis between production and excretion of uric acid is determined primarily by urate concentration in blood samples. In normal conditions, reference intervals are between 6.0 and 7.0 mg/dL, primarily gender variations [1]. Increased concentration levels in plasma are known as hyperuricemia and in urine as hyperuricosuria.