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Overview :
Pre-eclampsia is a serious condition both for the mother and
the fetus. It is associated with inadequate placentation and reduced blood
supply to the intravillous space of the developing placenta. Women who develop
pre-eclampsia show impaired resistance to the pressor effect of angiotensin II,
which can be demonstrated before the development of hypertension. Early
detection of patients at risk allows for early intervention.
Types of
pre-eclampsia:
(1)
nonproteinuric: rise in diastolic blood
pressure >= 25 mm Hg, AND diastolic blood pressure > 90 mm Hg, without
proteinuria
(2) proteinuric:
same as (1), with proteinuria > 1+ on dipstick
Specimen
Collection:
• random,
untimed urine sample
• collected
between 16 and 20 weeks of pregnancy
ratio of
inactive urinary kallikrein to creatinine =
= (inactive
urinary kallikrein in mU/mL) / (creatinine in µmol/mL)
where:
• conversion
factor for creatinine from mg/dL to µmol/mL should be 0.0884
Interpretation:
• median ratio
in women who developed pre-eclampsia was 78.27
• median ratio
in women who did not develop pre-eclampsia was 358.19
• a ratio <=
170 predicted pre-eclampsia with a sensitivity of 70% and specificity of 86%
NOTE:
Measurement of inactive urinary kallikrein does not appear to be readily
available in the US
at this time.
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