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New Test 'Aces' Preeclampsia Diagnosis


 

LISBON β€” A triple test for diagnosing preeclampsia during the third trimester was correct about 90% of the time in a pilot study with 46 women.

β€œThe generalizability of this test needs to be confirmed by using it on more women and on varied populations,” Dr. Brendan J. Smyth said at 15th World Congress of the International Society for the Study of Hypertension in Pregnancy.

A diagnostic test for preeclampsia during the third trimester would aid the management of these women by both making diagnosis during pregnancy more reliable and by paving the way for studies aimed at developing new interventions, said Dr. Smyth, a researcher at Abbott Laboratories in Abbott Park, Ill.

Currently, the only reliable way to distinguish preeclampsia from other blood pressure disorders of pregnancy is retrospectively. The appearance of new-onset hypertension during the final 20 weeks of pregnancy may be preeclampsia, but only if it resolves 12–24 weeks post partum. If it doesn't resolve, then it's chronic hypertension. Preeclampsia can also be hard to distinguish from gestational hypertension because proteinuria might lag behind the rise in blood pressure.

The three-tiered test developed by Dr. Smyth and his associates used serum tests for two biomarkers, body mass index (BMI), and supine systolic blood pressure.

The serum tests measured levels of soluble fms-like tyrosine kinase 1(sFlt-1) and placental growth factor (PlGF). Both factors are produced by the vascular endothelium during the growth of new blood vessels. The assays were run by Abbott Diagnostics, which is developing the tests; the tests are not yet commercially available. The specimens were collected in a study directed by Dr. Jason Umans, associate director of the General Clinical Research Center at Georgetown University in Washington, supported in part by a grant from the National Institutes of Health.

The diagnostic criterion was the ratio of these two analytes. If the ratio of sFlt-1/PlGF was less than 1.9, women were diagnosed as not having preeclampsia. If the ratio was 1.9 or greater, preeclampsia was diagnosed.

BMI was used to diagnose chronic hypertension. Women with a BMI of at least 34 kg/m

These diagnostic criteria were tested on 46 women and 85 of their serum specimens that were collected in the labor and delivery suites of two hospitals in Washington. The subjects included women with preeclampsia, chronic hypertension, superimposed preeclampsia on chronic hypertension, and healthy controls. All of the preeclampsia diagnoses were confirmed by following the patients postpartum.

At least one specimen was collected from each woman in the study. Second, and in some cases third, specimens were collected at weekly intervals from women who remained in the labor and delivery suites for longer periods.

The serum tests correctly classified 83 of the 85 specimens (98%) based on whether they came from preeclamptic or nonpreeclamptic patients. BMI then correctly classified 37 of 43 patients (86%) for the diagnosis of chronic hypertension. Among 42 women without preeclampsia and a BMI of less than 34 kg/m

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