6. sample collection : Freshly obtained urine specimens were centrifuged at 1,500 rpm for 10 min within 30 min of collection, aliquoted, and stored at _70°C until assayed. Dipstick detection for urine protein, pH, and gravity. Urine protein, pH, gravity, etc. were detected by Dipstick (Uri-Trak-3) in all urine specimens before being aliquoted for storage at _70°C. Urine protein was positive for all study subjects in mild and severe preeclamptic groups.