Amniotic fluid Flashcards
hCG production
Syncytiotrophoblast cells of placenta
hCG peak
1st trimester (blood, urine, amniotic fluid)
hCG subunit shared
Alpha (hCG, LH, FSH, TSH)
hCG specificity
Beta subunit
Pregnancy test principle
Enzyme immunoassay
Pregnancy test specimen
1st morning urine
Pregnancy kit cutoff
25 mIU/mL
Anti-hCG source
Rabbit
False-positive pregnancy test causes
Molar pregnancy, LH surge, hematuria, proteinuria, malignancies, postpartum, herbal meds, perimenopause, ovarian failure
False-negative pregnancy test causes
Early/late testing, dilute/adulterated urine, ectopic pregnancy, missed abortion
Hogben test
Female frog; positive: oogenesis
Galli-Mahini test
Male frog; positive: spermatogenesis
Friedmann test
Virgin rabbit; positive: corpora lutea/hemorrhagica
Ascheim-Zondek test
Immature mice; positive: ovarian hyperemia
Hyperemia in Preg test is also seen in
Kupperman/Kelso (virgin rat)
ELISA sensitivity
Positive at 10 days conception
Pregnancy urine SG
≥1.015
Amniotic fluid source
Placenta
Amniotic fluid functions
Cushion fetus, stabilize temp, movement, lung development
Amniotic fluid normal volume
800–1200 mL (3rd trimester)
1st trimester fluid source
Maternal circulation (35 mL)
Polyhydramnios causes
Decreased swallowing, NTDs, anomalies, infections
Oligohydramnios causes
Increased swallowing, membrane leakage, urinary deformities, malformations, premature membrane rupture, cord compression
Amniocentesis collection
30 mL in sterile syringe
Genetic defect assessment
2nd trimester amniocentesis (trisomy 21/Down syndrome)
Fetal lung maturity/HDN assessment
3rd trimester
Quadruple screen tests
Alpha-fetoprotein, HCG, unconjugated estriol (E3), inhibin A
FLM specimen handling
Ice delivery, refrigerated/frozen, filtration to prevent phospholipid loss
Cytogenetic study handling
Room temp or 37°C
HDN test specimen handling
Protect from light