A urine sample with pH 5.0, many uric acid crystals, and 20-50 RBC/hpf most strongly suggests which disease pattern?

A urine sample with pH 5.0, many uric acid crystals, and 20-50 RBC/hpf most strongly suggests which disease pattern?

• A. Gout
• B. Urinary tract infection
• C. Kidney stones
• D. Leukemia

Answer: (C)

Acidic urine promotes uric acid precipitation, so seeing many uric acid crystals in a urine sample taken at pH 5.0 strongly points to uric acid stone formation in the kidney or urinary tract. The presence of 20–50 red blood cells per high-power field indicates microscopic hematuria, which commonly occurs when stones irritate or injure the urinary tract lining as they pass. Taken together, this pattern is classic for kidney stones (uric acid nephrolithiasis) rather than other conditions. Gout involves urate crystal deposition in joints, not the urinary tract, so the uric acid crystals seen in urine don’t fit as well with a joint disease pattern. A urinary tract infection would typically show bacteria and inflammatory markers like leukocyte esterase or nitrites, rather than a predominance of uric acid crystals. Leukemia isn’t defined by this urinalysis pattern, and while tumor lysis can raise uric acid, it doesn’t explain the crystaluria and the specific stone-related hematuria described here.

Acidic urine promotes uric acid precipitation, so seeing many uric acid crystals in a urine sample taken at pH 5.0 strongly points to uric acid stone formation in the kidney or urinary tract. The presence of 20–50 red blood cells per high-power field indicates microscopic hematuria, which commonly occurs when stones irritate or injure the urinary tract lining as they pass. Taken together, this pattern is classic for kidney stones (uric acid nephrolithiasis) rather than other conditions.

Gout involves urate crystal deposition in joints, not the urinary tract, so the uric acid crystals seen in urine don’t fit as well with a joint disease pattern. A urinary tract infection would typically show bacteria and inflammatory markers like leukocyte esterase or nitrites, rather than a predominance of uric acid crystals. Leukemia isn’t defined by this urinalysis pattern, and while tumor lysis can raise uric acid, it doesn’t explain the crystaluria and the specific stone-related hematuria described here.