See Pregnancy & Prenatal Testing for more information on tests performed prior to and during pregnancy.
At a Glance
Why Get Tested?
When to Get Tested?
As early as 10 days after a missed menstrual period (some methods can detect hCG even earlier, at one week after conception) or when a doctor thinks that your symptoms suggest ectopic pregnancy, gestational trophoblastic disease, or germ cell tumors
A urine sample collected first thing in the morning or a blood sample drawn from a vein in the arm
Test Preparation Needed?
None needed; however, do not drink large amounts of fluid before collecting a urine sample for a pregnancy test because overly dilute urine may result in a false negative.
The Test Sample
What is being tested?
Human chorionic gonadotropin (hCG) is a hormone produced in the placenta of a pregnant woman. A pregnancy test is a specific blood or urine test that can detect hCG and confirm pregnancy. This hormone can be detected 10 days after a missed menstrual period, the time period when the fertilized egg is implanted in the woman's uterus. With some methods, hCG can be detected even earlier, at one week after conception.
During the early weeks of pregnancy, hCG is important in maintaining function of the corpus luteum. Production of hCG increases steadily during the first trimester (8–10 weeks) of a normal pregnancy, peaking around the 10th week after the last menstrual cycle. Levels then fall slowly during the remainder of the pregnancy. hCG is no longer detectable within a few weeks after delivery.
hCG is also produced by some germ cell tumors and increased levels are seen in gestational trophoblastic disease.
How is the sample collected for testing?
hCG is commonly detected in urine. The preferred specimen is a random urine sample collected first thing in the morning. hCG can also be measured in blood drawn from a vein in the arm.
NOTE: If undergoing medical tests makes you or someone you care for anxious, embarrassed, or even difficult to manage, you might consider reading one or more of the following articles: Coping with Test Pain, Discomfort, and Anxiety, Tips on Blood Testing, Tips to Help Children through Their Medical Tests, and Tips to Help the Elderly through Their Medical Tests.
Another article, Follow That Sample, provides a glimpse at the collection and processing of a blood sample and throat culture.
Is any test preparation needed to ensure the quality of the sample?
No test preparation is needed. However, do not drink large amounts of fluid before collecting a urine sample for a pregnancy test. This is because overly dilute urine may result in a false negative.
Ask a Laboratory Scientist
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NOTE: This article is based on research that utilizes the sources cited here as well as the collective experience of the Lab Tests Online Editorial Review Board. This article is periodically reviewed by the Editorial Board and may be updated as a result of the review. Any new sources cited will be added to the list and distinguished from the original sources used.
Sources Used in Current Review
Vorvick, L. (Updated 2010 November 21) HCG blood test – qualitative. MedlinePlus Medical Encyclopedia [On-line information]. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/003509.htm. Accessed March 2011.
Gaufberg, S. (Updated 2010 April 16) Early Pregnancy Loss. eMedicine [On-line information]. Available online at http://emedicine.medscape.com/article/795085-overview through http://emedicine.medscape.com. Accessed March 2011.
Pagana, K. D. & Pagana, T. J. (© 2011). Mosby's Diagnostic and Laboratory Test Reference 10th Edition: Mosby, Inc., Saint Louis, MO. Pp 558-560.
Grenache, D. et. al. (Updated 2011 January) hCG Testing – hCG. ARUP Consult [On-line information]. Available online at http://www.arupconsult.com/Topics/hCG.html?client_ID=LTD through http://www.arupconsult.com. Accessed March 2011.
(© 1995–2011). Unit Code 80678: Human Chorionic Gonadotropin (hCG), Quantitative, Pregnancy, Serum Mayo Clinic, Mayo Medical Laboratories [On-line information]. Available online at http://www.mayomedicallaboratories.com/test-catalog/Overview/80678 through http://www.mayomedicallaboratories.com. Accessed March 2011.
American Cancer Society. What is gestational trophoblastic disease? Available online at http://www.cancer.org/Cancer/GestationalTrophoblasticDisease/DetailedGuide/gestational-trophoblastic-disease-what-is-g-t-d through http://www.cancer.org. Accessed March 2011.
MedlinePlus Medical Encyclopedia. Gestational Trophoblastic Disease. Available online at http://www.nlm.nih.gov/medlineplus/ency/article/007333.htm. Accessed March 2011.
Enrique Hernandez, MD, FACOG, FACS. Gestational Trophoblastic Neoplasia. Available online at http://emedicine.medscape.com/article/279116-overview through http://emedicine.medscape.com. Accessed March 2011.
Ann M. Gronowski, Corinne R. Fantz, Curtis A. Parvin, Lori J. Sokoll, Carmen L. Wiley, Mark H. Wener, and David G. Grenache. Use of Serum FSH to Identify Perimenopausal Women with Pituitary hCG. Clin. Chem., Apr 2008; 54: 652 - 656.
One-Year Experience with Day-of-Surgery Pregnancy Testing Before Elective Orthopedic Procedures. Kahn, RL et al. Anesthesia & Analgesia April 2008. Vol. 106. No. 4 Pp 1127-1131.
Sources Used in Previous Reviews
Thomas, Clayton L., Editor (1997). Taber's Cyclopedic Medical Dictionary. F.A. Davis Company, Philadelphia, PA [18th Edition].
Pagana, Kathleen D. & Pagana, Timothy J. (2001). Mosby's Diagnostic and Laboratory Test Reference 5th Edition: Mosby, Inc., Saint Louis, MO.
(2003 June 23). Free Beta-Subunit of Human Chorionic Gonadotropin (Free b-hCG) Enzyme Immunoassay Test Kit. BioCheck, Inc. [On-line package insert]. PDF available for download at http://www.biocheckinc.com/inserts/bc-1023_fbhcg.pdf through http://www.biocheckinc.com.
Newberger, D. (2000 August 15). Down Syndrome: Prenatal Risk Assessment and Diagnosis. American Family Physician [On-line journal]. Available online at http://www.aafp.org/afp/20000815/825.html through http://www.aafp.org.
Qin, Q., et. al. (2002). Point-of-Care Time-resolved Immunofluorometric Assay for Human Pregnancy-associated Plasma Protein A: Use in First-Trimester Screening for Down Syndrome [Pages 1-3 of 20]. Clinical Chemistry 48:473-483 [On-line journal]. Available online at http://www.clinchem.org/cgi/content/full/48/3/473 through http://www.clinchem.org.
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Hoffman, B. and Johnson, J. (2004). Toronto’s Mount Sinai Hospital offers First-Trimester Screening Across Ontario. Healthcare Quarterly 7(2). PDF available for download at http://www.mountsinai.on.ca/Resources/HQ72MtSinaiProfile.pdf through http://www.mountsinai.on.ca.
Paralloi, A. (August 13, 2003, Edited) Second Trimester Maternal Serum Screening Programmes for the Detection of Down's Syndrome. Geneva Foundation for Medical Education and Research [On-line information, 8th Post Graduate Course]. Available online through http://www.gfmer.ch.
First Trimester Prenatal Screening. Alfigen, The Genetics Institute, Laboratory Services [On-line information]. Available online at http://www.alfigen.com/laboratory_4_3.html through http://www.alfigen.com.
(2004). Germ Cell Tumors: Beta-Human Chorionic Gonadotropin. Specialty Laboratories, Use and Interpretation of Laboratory Tests, Books [On-line information]. Available online at http://oncology.specialtylabs.com/books/display.asp?id=544 through http://oncology.specialtylabs.com.
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(2000). What is Ultra-Screen. NTD Laboratories, Inc. [On-line information]. Available online at http://www.ntdlabs.com/ultraphys.html through http://www.ntdlabs.com.
Shaskan, J. (2004 May 31). Amniocentesis and CVS Tests Decline Despite Increase in Number of Older Mothers. ACOG [On-line news release]. Available online at http://www.acog.org/from_home/publications/press_releases/nr05-31-04-1.cfm through http://www.acog.org.
Wu, A. (2006). Tietz Clinical Guide to Laboratory Tests, Fourth Edition. Saunders Elsevier, St. Louis, Missouri. Pp 252-255.