(Images courtesy of @JoseTesser)

The ultrasound shows kidneys of normal size with increased echogenicity, without hydronephrosis.

Kidney biopsy would be premature in this case. Findings such as nephrotic range proteinuria or evidence of glomerulonephritis would prompt a more urgent biopsy. Try a less invasive test first!

Excellent choice! Based on the urine sediment and this patient’s disease process, this is an important test. Uric acid level is 18.9 mg/dL (normal 2.4-7.0 mg/dL)

Great choice! This patient’s LDH is 1621 U/L (normal 140-280 U/L)

We might send this test if we suspected a connective tissue disease (CTD), like systemic lupus erythematosus (SLE). This patient’s initial presentation does not suggest SLE or other CTD. Try again!

This patient’s clinical history and data thus far are not consistent with a urinary tract infection. Pick again!

Glomerular diseases with hypocomplementemia often present with nephritic syndrome. The absence of hematuria/dysmorphic red blood cells/red blood cell casts makes nephritic syndrome less likely. Choose another test!

This test would help us identify a new monoclonal gammopathy in this patient, but may not help us with the etiology of her diagnosis here.  Try something else!

Great choice! No schistocytes or helmet cells are seen on the peripheral smear.