hCG test

What is being tested?

The human chorionic gonadotropin (hCG) test is also known as the pregnancy test. This test measures the amount of the hormone hCG in your urine or blood.

The hCG test can be used to both confirm and monitor a pregnancy. hCG is usually present only when a female is pregnant.

hCG starts being produced by the placenta after the fertilised egg implants in the womb. During pregnancy, the amount of hCG doubles every 2 to 3 days.

Home pregnancy test kits test for hCG in your urine. You can buy these from supermarkets and pharmacies. The urine test can detect hCG from around the time of your first missed period.

The hCG blood test may detect pregnancy earlier — from about 1 week after conception. Your doctor can refer you for this blood test.

Why would I need this test?

The hCG blood test is more sensitive than the urine test. Your doctor might use this to:

• check if you are pregnant
• confirm a positive urine hCG test
• check that your pregnancy is developing normally

Blood hCG tests are also used to detect tumours that can produce hCG, such as:

• testicular cancer
• ovarian cancer

Blood hCG tests can monitor these tumours. This can help your doctor see if treatment is working or if the tumour has come back after treatment.

How to prepare for this test

No special preparation is required for the hCG test. However, if you are having a urine test, try not to drink much before your test. This can dilute your urine sample and cause a false negative result.

Understanding my results

Normally, hCG levels rise quickly in early pregnancy. But if something is wrong with your pregnancy, your hCG levels may be higher or lower than expected.

If you have a tumour that increases your hCG level:

• an increase in your hCG test result would suggest that the tumour is getting bigger
• a decrease in your hCG test result would suggest that the tumour is getting smaller