Testing
Levels of hCG may be measured in the blood or urine. Most commonly, this is done as a pregnancy test, intended to indicate the presence or absence of an implanted embryo. Testing for hCG may also be done when diagnosing or monitoring germ cell tumors and gestational trophoblastic disease.
As pregnancy tests, quantitative blood tests and the most sensitive urine tests usually detect hCG between 6 and 12 days after ovulation. However, it must be taken into account that total hCG levels may vary in a very wide range within the first 4 weeks of gestation, leading to false results during this period of time.
Gestational trophoblastic disease like Hydatidiform moles ("molar pregnancy") or Choriocarcinoma may produce high levels of βhCG (due to the presence of syncytialtrophoblasts- part of the villi that make up the placenta) despite the absence of an embryo. This, as well as several other conditions, can lead to elevated hCG readings in the absence of pregnancy.
hCG levels are also a component of the triple test, a screening test for certain fetal chromosomal abnormalities/birth defects.
Read more about this topic: Human Chorionic Gonadotropin
Famous quotes containing the word testing:
“Now I see that going out into the testing ground of men it is the tongue and not the deed that wins the day.”
—Sophocles (497–406/5 B.C.)
“Is this testing whether I’m a replicant or a lesbian, Mr. Deckard?”
—David Webb Peoples, U.S. screenwriter, and Ridley Scott. Rachel, Blade Runner, being tested to determine if she is human or machine (1982)
“Today so much rebellion is aimless and demoralizing precisely because children have no values to challenge. Teenage rebellion is a testing process in which young people try out various values in order to make them their own. But during those years of trial, error, embarrassment, a child needs family standards to fall back on, reliable habits of thought and feeling that provide security and protection.”
—Neil Kurshan (20th century)