[Clinical significance of the laboratory determinations in preeclamptic patients]

To determine the clinical significance and optimal cutting points of laboratory tests more frequently used in patients with pre-eclampsia of recent diagnosis.

We made an analytic cross-sectional study for evaluation of diagnostic test. Non probabilistic sampling. Sample size 400 patients. We used the American College of Obstetricians and Gynecologists criteria as gold standard. Laboratory personnel was blinded to the clinical classification of the patients.

We studied 192 patients without pre-eclampsia, 63 with mild and 153 with severe pre-eclampsia. Hematocrits, prothrombin time, partial thromboplastin time, aspartate aminotransferase, alanine aminotransferase and bilirubins did not show significative differences among groups. Platelets counting showed low sensitivity. Lactic dehydrogenase showed 71% sensitivity (65-85 CI95%), specificity 74% (68-80 CI95%) positive likelihood ratio 2.7 and negative 0.4. Uric acid showed sensitivity of 75% (69-81 CI95%) specificity 79% (73-85 CI95%) positive likelihood ratio of 3.5 and negative of 0.3. Seric creatinine with sensitivity of 81% (76-86 CI95%) specificity of 60% (53-67 CI95%) positive likelihood ratio of 2 and negative of 0.3.

Seric uric acid, seric creatinine and lactic dehydrogenase are useful for diagnosis and severity classification of pre-eclampsia. Platelets counting is not useful for diagnosis but is useful for severity classification. In patients with thrombocytopenia prothrombin time is useful for severity classification.