serology of pregnancy Flashcards
HCG is…
Human Chorionic Gonadotropin
glycoprotein hormone
secreted by trophoblastic cells
When is HCG detected in pregnancy?
within a few days after conception
peaks during 2-3 months
what are the HCG subnunits?
alpha (blue aa chain) [shared w/ TSH, FSH, LH]
beta (green aa chain) [specific to HCG]
Which subunit of HCG is used for testing?
beta subunit
clinical usefulness of abnormal HCG testing
high risk pregnancy
ectopic pregnancy
trophoblastic tumors
detection of ectopic pregnancy (hydatidiform mole, choriocarcinoma)
testicular tumors
choriocarcinoma
epithelial malignancy of fetal orgin
develops from chorionic portion of the products of conception
dissemination, cause bleeding, contain components of ab. fetus, arise in men from testicular teratoma
testicular tumors
embryonic germ cell tumor with cells from the 3 germ layers
produce HCG
The first morning urine specimen is usually recommended in testing for urine HCG because
The specific gravity is highest in this sample and low specific gravity may cause a false negative test result and It contains the greatest concentration of HCG for a qualitative determination
The hormone which elevates in pregnancy and is used as a detection marker is:
Human chorionic gonadotropin
Indicate ALL the infectious agents listed below that are tested for in the TORCH test
Toxoplasma
gondii
Rubella virus
Cytomegalovirus
Herpes virus
Which of the following individuals would be
least likely
to be severely affected by a cytomegalovirus infection?
a 10-year old child
a heart transplant patient
a three week premature infant
an AIDS patient
a 10-year old child
A healthy 20 year old woman showed a
1
:32 titer of rubella IgG antibodies with no clinical symptoms. What is indicated by thisfinding?
Developed immunity at some time in the past
Which populations are of most concern regarding transmission of CMV in transfused blood?
transplant patients
premie babies
What will cause elevations in a pregnancy test?
pregnancy
testicular tumor
hydatiform mole
choriocarcinoma
A pregnant woman is exposed to a child with a rubella infection. She had no clinical symptoms but had a rubella titer performed. The titer was less than 1:8. Three weeks later, she had a repeat test and the titer was1:128. She still had no clinical symptoms. Was the laboratory finding indicative of rubella infection?
Yes, a greater than fourfold rise in titer is indicative of early infection in this case.
If antibody against the appropriate subunit is not used in the development of the test system for pregnancy testing, other hormoneswith a shared subunit may cross-react and cause a false positive result. Which hormones share a subunit with HCG?
TSH (thyroid stimulating hormone)
FSH (follicle stimulating hormone)
LH (leutinizing
hormone)
To confer specificity (eliminate false negatives) in a pregnancy test, a manufacturer can BEST
Develop a monoclonal antibody to the beta subunit of the HCG molecule as the test antibody
Older methods of pregnancy testing
agglutination
agglutination inhibition
current method of pregnancy testing
monoclonal antibody tests:
EIA method (sandwich technique)
modular methods
home pregnancy tests
modular methods of pregnancy testing test method
add sample, moves by wicking action, control line (dye imbedded in strip), test line anti HCG w/ dye + color w/ Antigen/antibody complex
home pregnancy tests test method
lamminar flow immunoassay
similar to modular methods
hCG hormone ranges during week:
week 1-3: 5-50
week 4: 10-425
week 5: 19-7,340
wk 6: 1,080- 56,500
wk 7-8: 7,670-229,000
wk 9-12: 25,700-288,000
wk 13-16: 13,300- 254,000
wk 17-24: 4,060- 165,400
wk 25-40: 3,640- 117,000
why test pregnant women for toxoplasmosis?
can result in CNS malformations or prenatal mortality in neonates
toxoplasmosis characteristics
coccidian parasite
worldwide
host: cat
