During routine urinalysis, 1-2 hyaline casts per high-power field are found with otherwise normal results. What is the most appropriate interpretation?

• A. Collect urine for culture and sensitivity
• B. Do nothing, since these casts are considered normal
• C. Refer the patient to a nephrologist
• D. Schedule for a CT scan

Answer: (B)

Hyaline casts are the most common type of urinary cast and are made primarily of Tamm-Horsfall protein. They’re non-specific and can appear with normal aging, concentrated urine, mild dehydration, exercise, or fever. Seeing a small number—about 1 to 2 per high-power field—while the rest of the urinalysis is normal is considered a benign, physiologic finding rather than evidence of renal disease.

Because there’s no other abnormality in the urinalysis and the patient is asymptomatic, the appropriate interpretation is to do nothing further at this time (no culture, no nephrology referral, and no imaging). If future tests show additional abnormal casts, proteinuria, hematuria, or other signs of kidney dysfunction, that would prompt further evaluation.