Human Chorionic Gonadotropin (hCG)

hCG (Human Chorionic Gonadotropin) Test, Pregnancy Test

What Affects the Test

Things that may affect the results of your test include:

• Doing a urine test for human chorionic gonadotropin (hCG) very early in pregnancy (during the first week after implantation) or on a urine sample taken in the middle of the day. The test may not always show an early pregnancy.
• HCG results may remain high (positive) for up to four weeks after a miscarriage (spontaneous abortion) or therapeutic abortion.
• Getting an injection of hCG to treat infertility. This may cause test results to appear high for several days after the injection.
• Having blood in the urine sample or soap in the collecting container, which may change the hCG level.
• Using diuretics and promethazine (such as Phenergan, Prorex, or Anergan). These medicines can cause false low hCG levels in urine test results.
• Using heparin, a medicine to prevent blood from clotting (anticoagulant)
• Using some medicines. These include hypnotics (such as Ambien), antipsychotics (such as Mellaril, Stelazine, and Serentil), and antinausea medicines (such as Compazine and Phenergan). Be sure to tell your doctor what medicines you take.

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Author:	Sandy Jocoy, RN	Last Updated: May 14, 2008
Medical Review:	Sarah Marshall, MD - Family Medicine Siobhan M. Dolan, MD, MPH - Reproductive Genetics
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