Final answer:
The hCG discriminatory zone is a range of hCG levels that can distinguish between a viable intrauterine pregnancy and a pregnancy that is not viable or may be located outside the uterus.
Step-by-step explanation:
The hCG discriminatory zone is a concept used in pregnancy testing to determine if a pregnancy is progressing normally. It refers to the range of hCG levels in the blood or urine that can distinguish between a viable intrauterine pregnancy and a pregnancy that is not viable or may be located outside the uterus.
Typically, hCG levels below the discriminatory zone indicate that the pregnancy is not progressing normally and may be at risk for a miscarriage or ectopic pregnancy. On the other hand, hCG levels above the discriminatory zone suggest a viable intrauterine pregnancy.
For example, in a certain study, the discriminatory zone for transvaginal ultrasound was defined as an hCG level of 1,500-2,000 mIU/mL. Any hCG level below this range was associated with a high likelihood of a non-viable pregnancy or pregnancy of unknown location.