What is a common laboratory finding in children with acute glomerulonephritis?

In children with acute glomerulonephritis, one of the hallmark laboratory findings is hematuria, which refers to the presence of blood in the urine. This condition typically arises as a result of inflammation in the glomeruli, the filtering units of the kidneys. When the glomeruli become inflamed, they may allow red blood cells to leak into the urine, leading to hematuria. This finding is often accompanied by other abnormalities, such as proteinuria (excess protein in the urine) or oliguria (decreased urine output), which together reflect issues with kidney filtering capabilities.

The other findings listed are not as characteristic in this context. Hypernatremia, which is an increased sodium concentration in the blood, would not typically occur in acute glomerulonephritis. Low serum albumin is more often associated with nephrotic syndrome rather than glomerulonephritis, where significant protein loss occurs. Hypocalcemia, a low calcium level in the blood, is not a common finding associated with acute glomerulonephritis either. Therefore, hematuria stands out as the definitive laboratory finding linked to this condition.