Background Signs and symptoms of Preeclampsia (PE) is one of the commonest reasons for referral for urgent assessment in pregnancy. PE defined as sustained BP ≥140/90 mmHg + proteinuria (PCR≥30 or ≥0.3g/24hr). NICE guidance (Hypertension in pregnancy 2010) acknowledges the lack of robust evidence to inform biochemical and haematological assessment, suggesting they do not predict progression to PE.

Methods A retrospective analysis was undertaken over a 12 month period of all pregnant women with signs or symptoms of PE who were referred for assessment at a tertiary centre. All underwent blood pressure monitoring and automated urine dipstick for protein (+/-PCR). Blood tests to assess; kidney function, electrolytes, FBC and transaminases were taken where indicated. Assessment of these biochemical measurements at the time of a final diagnosis (PE/Gestational hypertension/Gestational proteinuria) has been made to give a statistical appraisal of the effectiveness of each test as a diagnostic tool in PE.

Findings 164 women referred to the unit had bloods taken at the time of final diagnosis. Abnormal urate, creatinine, platelets and alanine-transaminase were assessed for sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and likelihood ratios (LR+ and LR-) for diagnosing PE (table).

Interpretation Biochemical and haematological assessments perform poorly at confirming PE, however the high specificity finding is consistent with NICE in that they are beneficial as ‘rule out’ tests.