HCG is what is tested for in urine or blood during a pregnancy test.
There are two subunits of this molecule: sort of a right half and a left half, but in this case it’s an alpha and a beta.
Oddly the alpha half of the HCG molecule made by the placenta is the same for HCG, TSH (a thyroid test), LH (the molecule of ovulation), and FSH (it goes up in menopause.
So, it is possible that abnormalities of these hormones can be misdiagnosed as an HCG elevation, and thus misdiagnosed as a pregnancy.
Most laboratories have nipped this problem in the bod
Not every positive pregnancy test, even just testing for the beta ‘left hand’ of the HCG molecule is really a normally developing uterine pregnancy.
Some cancers, some tubal pregnancies (ectopic pregnancy), some miscarrying pregnancies, and the pituitary gland itself can produce a very low level (but unchanging) of HCG, so it’s important to be evaluated by a gyno.