Pregnancy blood test (quantitative hCG)

What it measures

The developing placenta makes hCG soon after an embryo implants. In a healthy early pregnancy the level usually climbs quickly over the first weeks, but the pace varies. A slow rise can point to an ectopic pregnancy or a miscarriage, and a single number can't tell where a pregnancy is or whether it is healthy. Some fertility drugs contain hCG, and rare tumors also make it.

Who should consider it

• People who want an earlier or exact answer than a home test gives
• People with a positive home test who want confirmation
• People whose clinician wants to track hCG in early pregnancy

How to read your result

• Use the range on your report. Labs print cutoffs for negative, positive, and unclear results.
• One hCG value can't confirm a healthy pregnancy or rule out an ectopic pregnancy. Clinicians compare two levels about 48 hours apart and use ultrasound.
• A low but positive result can mean very early pregnancy, a miscarriage, or an ectopic pregnancy.
• This test does not replace prenatal care.

Reference ranges differ between labs. Use the range printed on your own report.

When to get care right away. Belly or pelvic pain, shoulder pain, heavy vaginal bleeding, dizziness, or fainting in early pregnancy can mean an ectopic pregnancy, which needs emergency care. Call 911 or go to the emergency room.

What to do next

With a positive result, set up prenatal care with a clinician. With an unclear or unexpected result, repeat it in about 48 hours as your clinician advises.