What does Liley graph measure?
In 1961 Liley developed a chart of changing amniotic fluid bilirubin levels (delta OD450) and gestation, with three zones delineating the severity of rhesus disease. This chart ranged from 27 to 40 weeks and was found to be clinically useful.
What is OD 450 amniotic fluid?
Amniotic fluid Δ OD 450 was standardized by dividing the actual value by the value on the line between zones 1 and 2 for corresponding gestational age. Standardized hemoglobin concentrations were defined as the number of standard deviations that the actual value deviated from the normal mean for gestational age.
What is Liley zones?
The Liley curve is divided into three zones. A result in Zone I indicates mild or no disease. Fetuses in zone I are usually followed with amniocentesis every 3 weeks. A result in zone II indicates intermediate disease. Fetuses in low Zone II are usually followed by amniocentesis every 1-2 weeks.
Does anti E cross the placenta?
The maternal IgG antibodies produced will pass through the placenta and attack fetal red cells carrying the corresponding antigen. Allo-immune hemolytic disease of the fetus and newborn caused by anti-E rarely occurs.
What is Rh incompatibility?
Rh incompatibility occurs when a woman who is Rh-negative becomes pregnant with a baby with Rh-positive blood. With Rh incompatibility, the woman’s immune system reacts and creates Rh antibodies. These antibodies help drive an immune system attack against the baby, which the mother’s body views as a foreign object.
What is Delta optical density?
The net absorbance, or delta A450, is calculated by measuring the difference between the patient’s curve and a theoretical baseline drawn between 560 and 350 nm. The delta A450 is then plotted against the gestational age on a Liley graph.
What is Delta OD?
Lab Name Bilirubin (delta OD 450), Amniotic Fluid Lab Code ABILG Epic Ordering Bilirubin (delta OD 450), Amniotic Fluid Description. The optical density scan of amniotic fluid allows for the assessment of bile pigments at 450 nm. If needed, interference from hemoglobin is removed using chloroform extraction.
What causes anti-E in pregnancy?
Hemolytic disease of the newborn (anti-RhE) is caused by the anti-RhE antibody of the Rh blood group system. The anti-RhE antibody can be naturally occurring, or arise following immune sensitization after a blood transfusion or pregnancy.
How does anti-e affect pregnancy?
Anti-E alloimmunization can cause fetal anemia, and the incidence could be underestimated [5]. Only a few reports of pregnancy loss due to anti-E were described [4, 6]. Unlike anti-D alloimmunization, anti-E titer is less sensitive in detecting severity of hemolysis in the subsequent pregnancy.
What is Rh positive mean?
Most people are Rh positive, meaning they have inherited the Rh factor from either their mother or father. If a fetus does not inherit the Rh factor from either the mother or father, then he or she is Rh negative. When a woman is Rh negative and her fetus is Rh positive, it is called Rh incompatibility.
