Reproductive System (Test of Pregnancy and Fetal well-being)

Question 1

-hCG production starts a few days after ________, and before _________

-it enters maternal circulation immediately after ____________

-hCG concentration in maternal blood rises exponentially, doubling every__ days

-excellent marker for confirming pregnancy

-levels detectable by some pregnancy tests within __-__ days post-implantation and should be detectable by all tests within __ days

Answer 1

fertilization; implantation

implantation

2

3-4
7

Question 2

-hCG levels rise sharply and peak about __-___ weeks after fertilization

-it then sharply decreases to a stable low level for the remainder of gestation

Answer 2

8-10

Question 3

hCG Structure

-glycoprotein composed of 2 polypeptide subunits: alpha and beta joined non-covalently

-____ subunit identical pituitary hormones FSH, LH and TSH

-___ subunit unique to hCG

-commercial test kits are generally beta-specific

Answer 3

alpha

beta

Question 4

Qualitative hCG Analysis

-_________ test using serum or urine is used to confirm pregnancy

-specimen collection
—–serum: _______ sensitivity than urine in earliest weeks of pregnancy

—–urine: _______ _______ specimen preferred; most concentrated; other/more dilute urine may test negative initially

Answer 4

Qualitative

greater

first morning

Question 5

this Qualitative hCG test uses solid phase, double-antibody, enzyme immunoassay
-utilizes 2 antibodies that recognize different epitopes on hCG molecule:
—–one specific for alpha subunit
—–other specific for beta subunit

sandwich assay:
1st Ab is anti-____, mouse monoclonal
2nd Ab is anti-___, goat polygonal

-_____-______ system
—-reagents immobilized on membrane of reaction disc

-reaction disc contains “On Board Controls: 1 negative and 1 positive

sensitivity:
detects hCG as low as 25 mIU/mL
(as early as 3-4 days after implantation)

Answer 5

Test Pack +Plus hCG COMBO with OBC

anti-alpha
anti-beta

flow-through

Question 6

Test Procedure

Specimens and reagents should be at room temperature

1. remove disc from the pouch
2. draw specimen to the line marked on the transfer pipette supplied
3. dispense contents into the Sample Well
   ——-specimen migrates across the membrane
   ——-you will see a light pink colour move through the window
4. read results at exactly __ minutes

Answer 6

5

Question 7

Basic Test Principle

-specimen (serum/urine possibly containing hCG) migrates across membrane & reacts with/mobilizes (makes it move) the first antibody: anti-alpha hCG antibody complex

-this first complex continues to migrate across membrane to react with/be captured by immobilized anti-beta hCG antibody (capture region), then continues to end of membrane

-if hCG is present in specimen it is detected by the enzyme-labelled-antibody which converts a colourless substrate to a coloured chromogen = positive test

Question 8

How does it work?

Question 9

How does it work?

Question 10

How does it work?

Question 11

How does it work?

Question 12

How does it work?

Question 12

How does it work?

Question 13

Limitations

False ________
-urine specimen too dilute
-specimen collected too early in pregnancy

False ______
-some post-menopausal specimens (low hCG levels unrelated to pregnancy)
-conditions other than pregnancy (hCG-producing tumours e.g. choriocarcinoma)
-nonspecific hCG-like substances

-specimens that originally test as positive during first few days post-conception may later be negative due to natural termination of pregnancy
——occurs in 31% of all pregnancies (22% are unrecognized)
——-request a repeat test (using serum specimen)

-urine preservatives which lower specimen pH < 3 will interfere

Answer 13

Negative

Positive

Question 14

Quantitative analysis of hCG

useful when qualitative testing inconsistent with clinical evidence

1. diagnosis of ________ pregnancy
   —–implantation outside uterus
   —–hCG levels are lower for gestational age
   —–collect serial specimens
   ——hCG levels fall rather than rise
   ———-normal pregnancy: levels double every 48 hrs between 4 and 7 weeks gestation——–
2. impending spontaneous abortion (miscarriage)
3. multiple pregnancies (______ levels)

4.detection & follow-up of hCG-producing tumours
——tumour marker test
——-germ cell tumours (ovary, testes)

5. Down Syndrome

Answer 14

ectopic

higher

Question 15

Suspected Ectopic Pregnancy

Questions the lab can answer:
1.Is the patient pregnant?
2.Are the quantitative hCG levels normal for history?
3.Is hCG rising normally?

Question 16

Role of estrogen

There are different estrogens but the most common are:

-_______: secreted by ovaries
-_______
-_______: secreted by placenta; predominant form during pregnancy
————-promotes blood flow between uterus and placenta
————-production requires a functioning placenta and a viable fetus

Answer 16

Estradiol
Estrone
Estriol

Question 17

Urinary _________ Measurement

-complementary relationship exists between the fetal adrenal glands and the placenta (“fetoplacental unit”)
———fetal estriol crosses placenta, is conjugated by maternal liver, & excreted in mother’s urine

-maternal urinary levels increase gradually until 12th week, then more rapidly until term

-level of urine estriol is an indicator of fetal & placental well-being

-test has largely been replaced by fetal monitoring and ultrasound

Answer 17

Estriol

Question 18

Assessment of Fetal Lung Maturity (FLM)

_______ _________ ________
-effects 10-15% premature babies
-lungs underdeveloped & collapse
-deficiency of pulmonary surfactant which coats alveolar epithelium to reduce surface tension; it is a mixture of phospholipids and proteins
-babies require supplemental oxygen & mechanical ventilation

Answer 18

Respiratory Distress Syndrome

Question 19

It is the biochemical test to predict the likelihood of RDS prior to preterm delivery; done with anticipated premature deliveries to assess and weigh risks to newborn

Answer 19

lecithin-to-sphingomyelin ratio (L/S ratio)

Question 20

Lecithin-to-Sphingomyelin ratio

_________- phospholipid
_________- protein

-laboratory analysis done before birth
—-specimen type: _______ _______
—-method: _____ ______ _______(TLC)
—-measure level of lecithin relative to sphingomyelin
—-L/S ratio rises with increasing gestational age, & correlates with fetal lung maturity

L/S ratio >___ indicates mature lungs & low risk for fetus having RDS

Answer 20

lecithin
sphingomyelin

amniotic fluid
Thin Layer Chromatography

2.0

Question 21

Assessment of Preterm Delivery

• ________ Delivery: labour occurring before 37 weeks gestation
  leading cause of perinatal morbidity & mortality
  ——–due to maternal, fetal, or infectious causes

-Symptoms:
–minimal cervical dilation, vaginal bleeding, cramping, back pain
–difficult to diagnose, hospitalized for observation

-non lab investigation = ultrasound
—–measure cervical length
——— <1.5 cm increased risk for pre-term birth

Answer 21

Preterm

Question 22

Fetal Fibronectin

-specimen: ________ swab

-solid phase enzyme immunoassay kit

-interpretation:
—–normally detectable during first ___ wks, then declines between __& ___ wks
—–fibronectin detection between 24-34 weeks indicates _______ risk
—–negative result indicates pregnancy will continue for at least 2 more wks

Answer 22

cervicovaginal

24; 24&34
increased

Question 23

Fetal Fibronectin
-large extracellular glycoprotein produced by chorion
-“trophoblastic glue”: found between FETAL MEMBRANES and PLACENTAL MEMBRANES
-can be detected in _______ _______
-If detected in maternal cervicovaginal fluids, at a specific gestational age, it indicates a LOSS OF MEMBRANE INTEGRITY

Answer 23

amniotic fluid