glycoprotein

structure of human chorionic gonadaotropin

“pregnancy hormone”

human chorionic gonadotropin is known as

trophoblasts

where is human chorionic gonadotropin synthesized?

trophoblasts

cells that contribute to development of the placenta and promote implantation of the embryo

• alpha: TSH, FSH, LH

• beta: unique to HCG

human chorionic gonadotropin subunits

first few weeks of gestation

rise of hCG

latter part of first trimester of pregnancy (approx. 2-3 mos after last menstrual period)

peak levels of hCG

• maintain corpus luteum

• stimulates production of progesterone (first 6-8 weeks)

function of hCG

25 mIU/mL

in a normal pregnancy, what is the detectable B-hCG secreted 2-3 days after implantation or 8-10 days after conception or fertilization

• detection of pregnancy

• gestational trophoblastic disease (hydatidiform mole)

• testicular tumor

• other HCG-producing tumors

uses of hCG

• direct: ultrasound

• indirect: hCG

direct and indirect method of detection of pregnancy

ectopic pregnancy

disappearance of hCG from blood after removal

1-31 days — median 8.5 days

ectopic pregnancy range from

ectopic pregnacy

rarely negative, almost always positive

1. Ascheim-Zondek

2. Friedman

3. Hogben

4. Galli-Mainini

5. Frank-Berman

6. Kupperman

bioassay for hCG

• complement fixation

• hemagglutination inhibition

• latex particle agglutination inhibition

• direct agglutination

• enzyme immunoassay (most common)

immunoassay for hCG

enzyme immunoassay / immunochromatography

principle of home based pregnancy test kit

1st morning urine

specimen for home based pregnancy test kit

25 mIU/mL

cut-off of home-based pregnancy test kit

rabbit

what is the source of anti-hCG in home based pregnancy test kit

≥ 1.015

urine for home based pregnancy test kit should have a specific gravity of:

false positive

PT interference: increased protein

false positive

PT interference: hydatidiform mole

false positive

PT interference: testicular tumor

false positive

PT interference: chorioepithelioma

false positive

PT interference: excessive ingestion of aspirin

false negative

diluted urine → undetectable levels of hCG