Table 11.12Calcium/creatinine ratio

Author, year, country, EL, study designNo. of women analysed, inclusion/exclusion criteria, age, gestational age at testReference standard used, incidence of PEIndex test cut-offResultsComments and conclusion
Rogers (1994)865 Hong Kong, EL II, cohort study199,
IN: normotensive primigravidas, singleton pregnancies
EX: congenital malformations
27.1 ± 3.8 years,
18–26 weeks
BP ≥ 140/90 mmHg ≥ twice
Prot. ≥ 0.3 g/litre,
Cresolphtalein method (American Monitor)/Beckman Astra-8 analyser
ST 49%, SP 90%
Conde (1994)866 Argentina, EL II, prospective cohort study387 women,
IN: normotensive nulliparas, singleton pregnancies
EX: diabetes mellitus, renal disease, proteinuria, chronic hypertension, other chronic medical illnesses
23.8 ± 5.7 years,
20 weeks
SBP ≥ 140 or DBP ≥ 90 mmHg twice ≥ 6 hours apart
Prot. ≥ 0.3 g/litre,
Colorimetric (direct)/picrato alcalino method
ST 33%, SP 78%, PPV 5%, NPV 97%Poor predictive values suggest that changes in the biochemical and haematologic tests occur only when pre-eclampsia has been established.
Kazerooni (2003)867 Iran, EL II, Prospective cross-sectional study102,
IN: nulliparas (18–35 years)
EX: renal disease, diabetes mellitus, proteinuria, chronic hypertension, other chronic medical illnesses
22.8 ± 4.5 years,
20–24 weeks
BP ≥ 140/90 mmHg or rise SBP ≥ 30 mmHg or DBP ≥ 15 mmHg twice ≥ 6 hours apart
Prot. ≥ 0.3 g/24 hours or ≥ 1+ dipstick,
≤ 0.001 mmol/litre (0.229 mg/100 ml: mg/100 ml)
ST 75%, SP
77.7%, PPV
20.7%, NPV
Single urine calcium to creatinine ratio may be an effective method for screening women at the greatest risk of pre-eclampsia.
Baker (1994)864 UK, EL II, A prospective, non- interventional study500,
IN: Normotensive nulliparas
EX: renal disease, chronic hypertension
Median 27 years (range 24–31),
18–19 weeks
DBP ≥ 90 mmHg twice ≥ 4 hours apart
Prot. ≥ 0.3 g/24 hours,
Perspective analyser (colorimetric)/Monarch centrifugal analyser (kinetic)
ST 31%, SP 55%

(correctly predicted 71%)

From: 11, Screening for clinical problems

Cover of Antenatal Care
Antenatal Care: Routine Care for the Healthy Pregnant Woman.
NICE Clinical Guidelines, No. 62.
National Collaborating Centre for Women's and Children's Health (UK).
London: RCOG Press; 2008 Mar.
Copyright © 2008, National Collaborating Centre for Women’s and Children’s Health.

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