| Where It's Done | Who Does It | How Long It Takes | Discomfort/Pain |
| Commercial laboratory or hospital. | Doctor, nurse, or lab technician. | 5 minutes or less to draw blood; less for urine sample. | Minor, from drawing blood. |
| Results Ready When | Special Equipment | Risks/Complications | Average Cost |
| A few minutes for urine test; 24 hours for precise blood test. | Supplies for drawing blood or container for collecting urine. | Negligible for drawing blood; none for urine test. | $ |
Blood or urine pregnancy test and human chorionic gonadotropin (hCG).
Purpose- To determine whether a woman is pregnant.
- To establish the stage of pregnancy (blood test only).
The blood or urine is analyzed for the pregnancy hormone, human chorionic gonadotropin (hCG), which is released by the chorion (the membrane that becomes the placenta) within six days of conception. hCG levels peak between the eighth and 12th weeks of pregnancy.
PreparationUrine collection is best done first thing in the morning when hCG concentrations are highest. Avoid drinking or urinating during the previous night.
Test procedureVarious testing techniques are used. The newest tests add blood or urine to monoclonal antibodies that recognize hCG. In the urine test, color changes signify the presence of hCG.
After the testYou may resume normal activities.
Factors affecting results- hCG may be present in blood up to four weeks after an abortion or miscarriage.
- hCG may be released by trophoblastic tumors (molar pregnancies)--uncommon, benign tumors that usually develop in the placenta but may also occur when a piece of the placenta is left behind in the uterus after delivery, miscarriage, or abortion.
- The presence of hCG in blood or urine signals pregnancy.
- The simplest urine test is quick and inexpensive but is not accurate until at least two weeks after a missed period. (A more complex, more accurate urine test takes two hours but can be used about a week after a missed period.)
- A blood test is generally more reliable than a urine test in very early pregnancy; it is almost always accurate by the 10th day after conception.
- A blood test detecting hCG can establish the stage of pregnancy, but ultrasound is more accurate and can reveal an ectopic (tubal) pregnancy.
- It is highly reliable. By the sixth week of pregnancy, tests are virtually 100% accurate.
- Blood tests are generally positive one to two weeks before urine tests.
- Blood tests can detect hCG levels.
- Urine tests are quick, inexpensive, and noninvasive.
- Urine tests may produce false-negative results a few days after conception.
- Urine tests only reveal presence of hCG.
If result is positive, you should be scheduled for regular prenatal care.
