hCG is a hormone secreted in pregnancy that is made by the developing embryo

Embryo

An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...

 soon after conception

Conception

Conception, or a concept, is an abstract idea or a mental symbol.Conception may also refer to:* Conception, or fertilisation, the fusion of gametes to produce a new organism.* Conception , an album by Miles Davis...

 and later by the syncytiotrophoblast

Syncytiotrophoblast

Syncytiotrophoblast is the epithelial covering of the placenta villous tree. It is a unique tissue in that it is a multi-nucleated, terminally differentiated syncytium, extending to 13m^2...

 (part of the placenta

Placenta

The placenta is an organ that connects the developing fetus to the uterine wall to allow nutrient uptake, waste elimination, and gas exchange via the mother's blood supply. "True" placentas are a defining characteristic of eutherian or "placental" mammals, but are also found in some snakes and...

) to maintain the fetal

Fetus

A fetus is a developing mammal or other viviparous vertebrate after the embryonic stage and before birth.In humans, the fetal stage of prenatal development starts at the beginning of the 11th week in gestational age, which is the 9th week after fertilization.-Etymology and spelling variations:The...

 viability preventing the disintegration of the corpus luteum

Corpus luteum

The corpus luteum is a temporary endocrine structure in mammals, involved in production of relatively high levels of progesterone and moderate levels of estradiol and inhibin A...

 of the ovary

Ovary

The ovary is an ovum-producing reproductive organ, often found in pairs as part of the vertebrate female reproductive system. Ovaries in anatomically female individuals are analogous to testes in anatomically male individuals, in that they are both gonads and endocrine glands.-Human anatomy:Ovaries...

 and thereby maintaining progesterone

Progesterone

Progesterone also known as P4 is a C-21 steroid hormone involved in the female menstrual cycle, pregnancy and embryogenesis of humans and other species...

 production that is critical for a pregnancy

Pregnancy

Pregnancy refers to the fertilization and development of one or more offspring, known as a fetus or embryo, in a woman's uterus. In a pregnancy, there can be multiple gestations, as in the case of twins or triplets...

 in humans; it also affects the immune tolerance of the pregnancy.

hCG is excreted in the urine

Urine

Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...

 of pregnant women. Detection of this hormone

Hormone

A hormone is a chemical released by a cell or a gland in one part of the body that sends out messages that affect cells in other parts of the organism. Only a small amount of hormone is required to alter cell metabolism. In essence, it is a chemical messenger that transports a signal from one...

 in urine or serum

Blood serum

In blood, the serum is the component that is neither a blood cell nor a clotting factor; it is the blood plasma with the fibrinogens removed...

 is an easy first method of diagnosis of pregnancy. The hormone can be detected as early as the sixth day after conception. hCG is also an important tumor marker

Tumor marker

A tumor marker is a substance found in the blood, urine, or body tissues that can be elevated in cancer, among other tissue types. There are many different tumor markers, each indicative of a particular disease process, and they are used in oncology to help detect the presence of cancer...

 because it is produced by some kinds of tumor

Tumor

A tumor or tumour is commonly used as a synonym for a neoplasm that appears enlarged in size. Tumor is not synonymous with cancer...

, such as: seminoma, choriocarcinoma

Choriocarcinoma

Choriocarcinoma is a malignant, trophoblastic and aggressive cancer, usually of the placenta. It is characterized by early hematogenous spread to the lungs...

, germ cell tumors, hydatidiform mole

Hydatidiform mole

Molar pregnancy is an abnormal form of pregnancy, wherein a non-viable, fertilized egg implants in the uterus, and thereby converts normal pregnancy processes into pathological ones. It is characterized by the presence of a hydatidiform mole...

 formation, teratoma

Teratoma

A teratoma is an encapsulated tumor with tissue or organ components resembling normal derivatives of all three germ layers. There are rare occasions when not all three germ layers are identifiable...

 with elements of choriocarcinoma

Choriocarcinoma

Choriocarcinoma is a malignant, trophoblastic and aggressive cancer, usually of the placenta. It is characterized by early hematogenous spread to the lungs...

, and

Pregnancy detection kits

Pregnancy test

A pregnancy test attempts to determine whether or not a woman is pregnant.These markers are found in urine and blood, and pregnancy tests require sampling one of these substances. The first of these markers to be discovered, human chorionic gonadotropin , was discovered in 1930 to be produced by...

 containing a strip or card impregnated with anti-hCG globulin

Globulin

Globulin is one of the three types of serum proteins, the others being albumin and fibrinogen. Some globulins are produced in the liver, while others are made by the immune system. The term globulin encompasses a heterogeneous group of proteins with typical high molecular weight, and both...

 are readily available. The test is executed by immersing the proper end of the strip in urine or sprinkling three drops of urine on the indicated site of a card. Result is readable within two to three minutes.

External links

• A descriptive animation of the principle behind a lateral-flow sandwich-ELISA home pregnancy test.

http://www.sutherlandhealth.com/companies/condomania/product-range/vision/hcg-pregnancy-midstream