A pregnancy test measures the amount of a hormone called human chorionic Gonadotropin (hCG). The hormone hCG is produced in pregnancy and can be found in the bloodstream and urine.
To determine if a woman is pregnant, hCG testing can be done as soon as 10 working days after conception. The measurement of hCG is also a good way to identify any complications that may occur during pregnancy.
The purpose of the test
A pregnancy test is used to determine if a woman is pregnant. This can be done with both urine and blood tests for the hCG. Repeat testing could confirm a pregnancy. Tests that measure hCG levels in pregnancy may be used to determine the fetus’ age.
H.C.G. is less common. H.C.G. tests can be used to:
- Identify and rule out an ectopic baby. This is when a fertilized egg attaches to or implants in an unusual area
- Pregnancy testing
- Prenatal screening for Down syndrome
- Monitor a pregnant woman at high risk for miscarriage
- Diagnose gestational tumoroblastic disease (G.T.D. A term used to describe pregnancy-related tumors.
What does this test measure?
A pregnancy test measures the amount of a hormone called human chorionic Gonadotropin (hCG). During pregnancy, hCG levels are higher. Two ways can hCG results be reported:
- Qualitative: The presence or absence of qualitative hCG in a sample will determine if a positive or negative result. Qualitative tests can either be performed with blood or urine samples. This type of testing is used most often to confirm a woman’s pregnancy.
- Quantitative: Quantitative testing for hCG measures the amount of hCG in blood. While these tests are often done with blood samples, some urine tests can also provide quantitative measurements. Quantitative hCG tests are also used to confirm a pregnancy.
When is it time to have a pregnancy test?
When a woman is suspected to be pregnant, a pregnancy test is usually done. A pregnancy test may be performed as early as 10 days after conception. Tests for pregnancy accuracy are more accurate if performed within 1-2 weeks of a missed period.
This may be done if there are signs and symptoms that indicate an ectopic pregnancy, or a failing pregnancy.
These are signs of an ectopic baby:
- Abnormal vaginal bleeding
- Low back pain
- Lower abdomen pain or pelvic pain
- Cramping one side of the pelvis
If an ectopic pregnancy does not get treated, it may lead to more severe symptoms. If you notice any of these symptoms, you should consult a doctor.
Pregnancy testing can also be routine prior to certain medical treatments such as chemotherapy or surgeries that could potentially cause harm to a fetus.
Only a doctor can determine if a test for pregnancy is necessary for a particular patient.
How to Find a Pregnancy Test
How to test
A health care professional must order laboratory tests like blood draws and urine samples. These tests can be done in a doctor’s office or hospital. You can also have your urine tested at home. Talk to your doctor if you think you might be pregnant.
Is it possible to take the test at my home?
Home pregnancy tests can be performed quickly and conveniently. Although home pregnancy testing is similar to the laboratory’s qualitative urine hCG test, there are important differences.
- You must follow the exact instructions for at-home tests. Follow the instructions carefully when using an at-home test. The test brand can affect the ability of each test to detect hCG.
- Be sure to read the instructions carefully regarding how long you should wait before testing after missing a period. If you wait too long to test, it could lead to negative results if you become pregnant.
- A urine sample should be taken from you the first time that you urinate each morning for home pregnancy testing. This is when the urine is most concentrated and contains enough hCG for detection.
Most at-home pregnancy tests yield the same results as a doctor’s qualitative urine test for hCG.
It is important that you contact your doctor if your pregnancy test comes back positive.
What is the cost of the test?
Cost of pregnancy testing is dependent on a number of factors including the person’s insurance coverage and the type of test.
The majority of pregnancy tests are covered by insurance if ordered by a doctor. For more information on specific costs, it is important to speak with your provider and health insurance.
The blood or urine sample is used to test for pregnancy.
- The blood test involves drawing blood from a vein on your arm. The doctor will perform the test and send the result to the laboratory.
- You can perform a urine test by placing a droplet of urine in a cup, and then urinating. You can do this in a doctor’s clinic or at your home with an at-home kit.
Before the Test
There is usually no need to fast or make any preparations prior to a blood or urine pregnancy test. It would be a good idea to always ask your doctor for clarification or confirmation of any pre-test instructions.
A health care professional will inform you if a blood or urine sample is required for a pregnancy test.
A needle will be inserted into your arm to take a sample of blood. To increase blood flow to the veins, an elastic band is placed around your upper arm before drawing blood. After the puncture site is cleaned, disinfection is applied. The needle blood draw can cause a slight sting, but it usually lasts less than one minute.
You will need to urinate in a cup provided by your healthcare provider to collect a sample of your urine. In most cases, a urine sample should be taken within the first hour of urinating in the morning. It takes just a few minutes to collect a urine sample.
After passing the test
To prevent bleeding, a cotton swab or band-aid will be applied after the blood draw. It is likely that you will be asked to keep the bandaid on for at least an hour.
A urine sample is not required for post-test instructions.
Pregnancy Test Results
Receiving test results
It depends on which type of pregnancy test you ordered. The time taken to receive the results will vary. A blood test results can take up to a few hours or more than one day. Results of urine tests usually take one to two minutes.
Both of these tests are usually performed in a clinic setting. You will most likely receive the results from your doctor.
Interpreting test results
The way pregnancy tests are reported varies depending on whether they were qualitative or quantitative.
Qualitative test results
Qualitative results from are reported as either positive or negative.
- Negative results indicate that the patient is not likely to be pregnant. Low hCG levels can cause false-negative results. If there is a possibility of pregnancy, the test might need to be repeated within a week.
- Positive results indicate that the patient is likely to be pregnant. False positives can happen in women who are post-menopausal and taking hormone supplements.
Quantitative test results
Quantitative results of quantitative tests are reported in milli-international units (mUI/mL). People who aren’t pregnant should not have hCG detected. The hCG level in pregnant women doubles every 2-3 days for the first 30 days. During the first trimester, hCG levels continue to rise and then slowly decrease during the second and subsequent trimesters.
Quantitative test results may be used if there is a concern about a pregnancy or other medical conditions.
Discussing your results with a healthcare professional is the best way for you to find out more about your health and what the next steps are.
Are the test results correct?
Although no pregnancy test is perfect, they are very accurate.
If a woman isn’t pregnant, a positive test can be given. If the test is performed too soon after conception, or if there are insufficient levels of hCG, a negative result can be given to a pregnant woman. A negative pregnancy test should not be performed if a suspicion of pregnancy is raised.
- Non-Invasive Prenatal Screening (NIPS)
- First Trimester Screening
- Maternal Serum Screening, Second Trimester
Other places on the Web
- C.D.C. : Healthy Pregnancy
- Womenshealth.gov: How to know if you’re pregnant
- MedlinePlus Medical Encyclopedia – Ectopic pregnancy
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