|
RELATED PREGNANCY TESTING
Acetylcholinesterase
Acetylcholinesterase(AC) in amniotic fluid samples that have elevated
AFP levels. It is not normally found in amniotic fluid; its presence is
associated with neural tube defects. It is measured on amniotic fluid
that have elevated AFP levels.
- Specimen: 2mL of amniotic fluid, stored at
2 to 8° C
- TAT: 7 -10 days (This is sent to a reference
lab)
Alpha-Fetoprotein
(AFP)
One of three serum tests (triple test: AFP, hCG, unconjugated estriol)
measured for screening for fetal Down Syndrome. The concentration of AFP
in amniotic fluid is 250 times greater than maternal serum levels: the
concentration of AFP in fetal blood is 150 times that i amniotic fluid.
When amniotic fluid AFP is elevated, assay of acetylcholinesterase is
useful in confirming the diagnosis of an open neural tube defect.>
- One mL amniotic fluid
- Accurate dating of gestation is essential for proper
interpretation
- TAT: Test is performed every Tuesday and Friday
Bilirubin
The severity of erythroblastosis fetalis (hemolytic disease of the newborn)
can be estimated by determining the amount of bilirubin in amniotic fluid.
Thus, when incompatible maternal antibodies are delivered to the fetus
by way of the placenta, they interact with fetal RBC's, causing hemolysis,
and thus, bilirubin is released.
- One mL amniotic fluid
- Accurate dating of gestation is essential for proper
interpretation
- TAT: One hour from arrival
Fetal Lung Maturity (FLM) test
The FLM test is useful for the assessment of fetal lung maturity in
deciding whether or not to deliver a preterm infant.
- One mL amniotic fluid or vaginal pool (if membranes
are ruptured)
- Contamination with blood or bilirubin necessitates
testing by an L/S ratio or DSL concentration
- Is accurate in diabetic pregnancies
- TAT: One hour from arrival
Progesterone
Serum progesterone testing is available to compliment serum hCG testing
to assist in the differential diagnosis of ectopic pregnancy during the
first 8 to 10 weeks of pregnancy.
- 1.5 mL of blood (serum, red top tube) is the minimum
required
- TAT: 24 hour TAT for routine orders. Two hour TAT
for STAT requests.
Triple test (AFP, Beta hCG, unconjugated estriol)
Using maternal serum, the measurement of the triple test markers is
capable of detecting 60% of Down syndrome pregnancies at a false positive
rate of 5%.
- 1.5 mL blood in serum tube
(red top, no anti coagulant)
- TAT: Performed every Tuesday and Friday
Human Chorionic Gonadotropin (hCG)
Serum hCG measurements are negative in non-pregnant women. Serum hCG
levels are usually detected 7 to 10 days after implantation, and should
double approximately every 2 days in a normal pregnancy.
- 2 mLs of blood (serum) are required for testing.
- TAT: Within 24 hours for routine orders. One hour
TAT for STAT requests
|
