What does a positive pregnancy test indicate?

A positive pregnancy test indicates the presence of human chorionic gonadotropin (hCG) in the individual's urine or blood, which is produced after a fertilized egg implants in the uterus. While a positive result is a strong indicator of pregnancy, it is not definitive proof of pregnancy on its own due to a few possibilities that could lead to a positive result, such as biochemical pregnancies or certain medical conditions.

The term "probable sign of pregnancy" accurately describes the positive test result, as it suggests that pregnancy is likely; however, it does not eliminate the chance of false positives or other factors that may lead to the same result. Therefore, additional clinical assessments and evaluations—such as an ultrasound or further hormone testing—may be necessary to confirm an ongoing pregnancy.

The other options misinterpret the implications of a positive test. "Guaranteed evidence of pregnancy" overstates the certainty of the test result, while "clinical sign" and "positive sign" do not capture the nuance that a positive test cannot definitively confirm pregnancy without further evaluation.