Background
Recent studies on Vietnamese children have shown that kidney diseases are not detected early enough to prevent chronic renal failure. The dipstick test is a simple and useful tool for detecting urinary abnormalities, especially in isolated or remote areas of Vietnam, where children have limited access to health care.

Methods
This cross-sectional study was conducted in 2011 at seven kindergartens in Can Gio district, Ho Chi Minh City, Vietnam. Two thousand and twelve children, aged 3 to 5, were enrolled. Morning mid-stream urine samples were examined by dipstick. Children with abnormal findings were re-examined with a second dipstick and underwent further investigations.

Results
Urinalysis was available for 1,032 boys and 980 girls. Mean age was 4.4 ± 0.8 years. Urinary abnormalities were detected in 108 (5.5%) of the subjects. Among them, nitrituria and leucocyturia accounted for more than 50%. Positive fractions of proteinuria, hematuria, nitrituria, leucocyturia, and combined nitrituria and leucocyturia after two dipsticks were 0.1%, 0.1%, 2%, 1% and 0.3%, respectively. Abnormal findings were more common in girls than boys (p < 0.001), and higher in communes with very low (< 50 persons/km2) population density (14.3% vs 4.1%, p < 0.001). A renal ultrasound detected four cases of hydronephrosis and one case of duplication of ureter.

Conclusions
The prevalence of urinary abnormalities in asymptomatic children in South Vietnam demonstrates the need for hygiene education among parents. Training for dipstick usage for all medical staff at health stations, especially in remote areas and in places with very low population density, is also clearly necessary. Routine urinalysis can be set up if a close control is conducted at locations.