Freda compared the ? OD450 of serial amniocentesis samples to determine severity of disease. This method divides affected patients into 4 groups.
Group
?OD450
Interpretation
1+
0 - 0.2
Unaffected or mildly affected fetus. No danger for the next 2 weeks.
2+
0.2 - 0.35
Affected fetus, but no danger for next 2 weeks.
3+
0.35 - 0.70
Fetal distress (severely affected infant), with death in 10+ days
4+
> 0.70
Severely affected infant that is typically hydropic and moribund. Fetal death within 1 week.
A problem with this method is that, while it works well early in gestation, beyond 32 weeks fetal death can occur with a ? OD-450 less than 3+.
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Specialty: Obstetrics & Gynecology, Clinical Laboratory
ICD-10: ,
