Bilirubin amniotic fluid

Specimen:

2 mL amniotic fluid.  Protect from light.

Method:

Spectrophotometry.

Reference Interval:

Varies with gestational age.

Some laboratories express the result as µmol/L, others as an ODD450 (optical density difference at 450 nm).

Application:

Investigation of pregnancies at risk for Haemolytic disease of the newborn.

Interpretation:

Increased levels indicate haemolysis.

A number of different graphs have been published correlating degree of risk with amniotic fluid bilirubin level at various gestational ages.

Bleeding into the amniotic fluid invalidates results.

Reference:

Oepkes D. Eur J Obstet Gynecol Reprod Biol 2000; 92: 83-89.