A comparison of 4- and 24-hour urine samples for the diagnosis of proteinuria in pregnancy

Preeclampsia is a serious complication of pregnancy,
and it is vital to diagnosis the condition as early as possible.
Proteinuria is an important symptom of preeclampsia,
and repeated urine analysis to screen for the condition is part
of the standard antenatal care. The purpose of this study was
to determine the correlation between 4- and 24-hour urine total
protein values to examine whether the 4-hour urine samples
could be used for the diagnosis of proteinuria in hypertensive
disorders of pregnancy.
Methods: A cross-sectional study was performed on 110
pregnant (after gestational week 20 of pregnancy) patients
who were hypertensive (blood pressure ≥140/90 mmHg) and
had proteinuria as defined by positive urinary protein of at
least 1+ in dipstick. Patients' urine samples were collected
over 24 hours; the first 4 hours were collected separately from
the next 20-hours. Patients, who did not collect the 24-hour
urine, were excluded from the study. One hundred patients
met the criteria, and were included in the study. The urine
volume, total protein and creatinine levels of 4- and 24-hours
samples were measured. The correlation between 4-hour and
24-hour samples was examined using Pearson correlation test.
Results: Of the 100 patients, 42 had no proteinuria, 44 had
mild proteinuria, and 14 had severe proteinuria. The urine protein
values of 4-hour samples correlated with those of the 24-
hours samples for patients with mild and severe forms of the
disease (P<0.001, r=0.86).
Conclusion: This study showed there was a correlation between
4-hour and 24-hour urine proteins. The finding indicates
that a random 4-hour sample might be used for the initial
assessment of proteinuria