Serologic testing to document recent streptococcal infection is helpful but does not prove causation, as a significant number of children are asymptomatic carriers Serologic tests available include titers for antistreptolysin O (ASO), antihyaluronidase, antistreptokinase, antinicotinamide-adenine dinucleotidase, and anti-DNAse B ASO may be negative in the setting of streptococcal cellulitis, and it is important to note that antibiotic therapy may blunt the increase in antibody titers The urine sediment will demonstrate glomerular erythrocytes and leukocytes, and may contain red cell casts Proteinuria is not uncommon, though not typically in the nephrotic range Renal biopsy is generally not indicated for the diagnosis of APSGN It may be considered if the clinical picture does not clearly support a diagnosis of APSGN, if renal function does not recover in an expected fashion, or if C3 levels remain persistently low Clinical management Therapy for APSGN is largely supportive although antibiotics should be initiated if active infection is still present Given the underlying glomerular inflammation and generally intact tubular function, there is a propensity for salt and water retention leading to edema and increased blood pressure Therefore, weight should be measured daily and blood pressure checked regularly during the early acute illness Children with hypertension or decreased renal function should be considered for admission If edema or hypertension is present, salt and fluid restriction should be initiated and diuretic therapy considered Furosemide can be provided at doses of 0.5 to mg/kg once to four times daily to optimize fluid balance If the child is hypertensive, short- or long-acting calcium channel blockers can be initiated while awaiting recovery If the blood pressure is significantly elevated, IV hydralazine 0.1 mg/kg can be given every to hours with appropriate dose adjustment until other supportive measures are effective If a child demonstrates persistent hypertension and proteinuria and if renal function has been stable, ACE inhibitors can be considered with close monitoring of serum creatinine and potassium The prognosis for complete recovery from the initial episode of APSGN is good, even for those who presented with renal insufficiency or hypertension Generally, the clinical symptoms of APSGN begin to improve after to weeks If reduced renal function and edema are evident at presentation, renal function begins to normalize and diuresis ensues within