Q. A 9-year-old boy is brought to the emergency department due to severe abdominal pain and bloody stools. He has no chronic medical conditions but he suffered from an upper respiratory infection 2 weeks ago. On examination, he has non-blanching skin lesions over his lower extremities, and passive dorsiflexion of his left foot elicits pain. You order a urinalysis and expect to find which of the following sets of results: Elevated protein (4.0 g/24h) as the only abnormality. No other abnormal findings. Mildly elevated protein (2.0 g/24h), only. Presence of RBCs, RBC casts, elevated IgA. Mildly elevated protein (2.0 g/24h), only. Presence of RBCs without RBC casts, elevated IgA. Elevated protein (4.0 g/24h) and RBC casts but no other abnormal findings.