In the absence of proteinuria, the presence of new-onset hypertension (elevated blood pressure) and the new onset of one or more of the following is suggestive of the diagnosis of pre-eclampsia:
Evidence of kidney dysfunction (oliguria, elevated creatinine levels)
Impaired liver function (noted by liver function tests)
Thrombocytopenia (platelet count <100,000/microliter)
Pulmonary edema
Ankle edema (pitting type)
Cerebral or visual disturbancesPre-eclampsia is a progressive disorder and these signs of organ dysfunction are indicative of severe pre-eclampsia. A systolic blood pressure ≥160 or diastolic blood pressure ≥110 and/or proteinuria >5g in a 24-hour period is also indicative of severe pre-eclampsia. Clinically, individuals with severe pre-eclampsia may also present epigastric/right upper quadrant abdominal pain, headaches, and vomiting. Severe pre-eclampsia is a significant risk factor for intrauterine fetal death. A rise in baseline blood pressure (BP) of 30 mmHg systolic or 15 mmHg diastolic, while not meeting the absolute criteria of 140/90, is important to note but is not considered diagnostic. Predictive tests
There have been many assessments of tests aimed at predicting pre-eclampsia, though no single biomarker is likely to be sufficiently predictive of the disorder. Predictive tests that have been assessed include those related to placental perfusion, vascular resistance, kidney dysfunction, endothelial dysfunction, and oxidative stress. Examples of notable tests include:

Doppler ultrasonography of the uterine arteries to investigate for signs of inadequate placental perfusion. This test has a high negative predictive value among those individuals with a history of prior pre-eclampsia.
Aspirin
Taking aspirin is associated with a 1 to 5% reduction in pre-eclampsia and a 1 to 5% reduction in premature births in women at high risk. The World Health Organization recommends low-dose aspirin for the prevention of pre-eclampsia in women at high risk and recommends it be started before 20 weeks of pregnancy. The United States Preventive Services Task Force recommends a low-dose regimen for women at high risk beginning in the 12th week. Benefits are less if started after 16 weeks.The more recent study ASPRE, besides its efficacy in identifying women suspected to develop pre-eclampsia, has also been able to demonstrate a strong drop in the rate of early pre-eclampsia (-82%) and preterm pre-eclampsia (-62%). The efficacy of aspirin is due to screening to identify high risk women, adjusted prophylaxis dosage (150 mg/day), timing of the intake (bedtime) and must start before week 16 of pregnancy. Physical activity
There is insufficient evidence to recommend either exercise or strict bedrest as preventive measures of pre-eclampsia. Smoking cessation
In low-risk pregnancies, the association between cigarette smoking and a reduced risk of pre-eclampsia has been consistent and reproducible across epidemiologic studies. High-risk pregnancies (those with pregestational diabetes, chronic hypertension, history of pre-eclampsia in a previous pregnancy, or multifetal gestation) showed no significant protective effect. The reason for this discrepancy is not definitively known; research supports speculation that the underlying pathology increases the risk of pre-eclampsia to such a degree that any measurable reduction of risk due to smoking is masked.