Urinary estrogen assays and maternal hyperbilirubinemia.

Urinary estrogen determinations have simplified the care of pregnant patients with certain metabolic disorders known to adversely affect the fetus. This report demonstrates that erroneously low values for urinary estrogens may be obtained if colorimetric assay methods are used for patients with congenital hemolytic anemias during an acute hemolytic crisis. This appears to be due to the interference of the large amounts of urobilin present in the urine of these patients.