What is the best method to use when quantifying proteinuria in children and adults: 24-hour urine collections for total protein, random urine protein:creatinine ratio or microalbumin:creatinine ratio? — Janet Goshorn, ARNP-BC, Clermont, Fla.

Developmental issues and severity of illness (hospitalized or outpatient) may influence your choice of test. It is possible to obtain a 24-hour urine specimen from children who are toilet-trained. The same is not true of infants and young toddlers who are still in diapers (unless catheterized for 24 hours). Therefore, a spot urine protein:creatinine ratio is the measurement of choice.

Microalbumin:creatinine ratio is recommended as part of routine surveillance in patients with conditions that increase the risk of kidney failure (e.g., diabetes). The purpose of this measurement is to detect kidney failure as early as possible. The urine protein:creatinine ratio is a very accurate measurement for monitoring persistent proteinuria, especially if the specimen is a first-morning void. Some studies have shown the urine protein: reatinine ratio to be a better predictor of progression to renal failure than the 24-hour urine specimen. — Julee B. Waldrop, DNP (176-4)

These are letters from practitioners around the country who want to share their clinical problems and successes, observations and pearls with their colleagues. We invite you to participate. If you have a question, submit it here.