1. Hi All- I would appreciate any thoughts on this case. The pictures are from urine sediment in a 9 week old Great Dane puppy who initially presented for hematuria and mild lethargy. The urine was dark red, sg 1.057, pH was 8.5, 3+ protein (dipstick), and RBCs were greater than 50/HPF. I thought the crystals were most consistent with cystine crystals. The hematuria resolved the following day and the puppy was clinically doing better. A urinalysis repeated 5 days later was yellow, s.g 1.055, pH was 8.5, 3+ protein, and no RBCs or WBCs. Crystals with similar morphology continued to be present. My primary question is if others have seen cystine crystals in alkaline urine? I discussed performing the Nitroprusside urine spot test to confirm cystinuria but I am concerned that the persistent proteinuria and alkaline urine could be due to other renal tubular abnormalities.