PREGNANCY DIAGNOSIS
The urine test kits that can be purchased at most pharmacies are very much like the ones used in doctor's offices and clinics. If you follow the directions carefully they are very accurate. Usually they will be positive about 2 days after your menstrual period was due if you are actually pregnant. If the test is positive it is about 99% accurate. If the test is negative you may not be pregnant or you may just be too early in pregnancy for the test to show.
Blood tests for pregnancy are almost 100% accurate and can diagnose pregnancy even before the woman misses her period. These tests can be obtained by a doctor's office or clinic.
The qualitative urine human chorionic gonadotropin (HCG) test is usually performed by placing a drop of urine on a prepared chemical strip. It usually takes one or two minutes for the strip to indicate the result. The qualitative and quantitative serum tests are performed by drawing a single tube of blood and sending it to a laboratory. You may wait anywhere from a few hours to more than a day to get the results. Quantitative tests are used to measure the level of HCG in your blood, and give your doctor more information than the qualitative test.
How it feels
The urine test merely involves normal urination into a cup. The serum tests involve drawing blood through a needle and into a tube. Any discomfort you might feel will only last a few seconds.
Risks
There are no medical risks associated with testing for pregnancy.
Why the test is performed
Qualitative tests
Women who are late for their "period" often perform qualitative urine tests at home. "Qualitative" means that the test will only indicate whether you are pregnant or not -- yes or no. Doing the test at home permits greater privacy. Home pregnancy tests are available at pharmacies and do not require prescriptions.Sometimes, the test will be performed at your doctor’s office before the first prenatal visit. This is done just to confirm that you are actually pregnant. Doctors also perform a qualitative urine pregnancy test to rule out pregnancy before starting a medication or therapy that might adversely affect an existing pregnancy.
Qualitative serum pregnancy testing is performed when greater accuracy is sought, but only a "yes" or "no" answer is required. While the qualitative urine test can detect HCG levels above 25-50 milli-international units per milliliter (mIU/mL), the serum tests can detect HCG levels above 5-10 mIU/mL.
Quantitative tests
"Quantitative" serum pregnancy testing is usually performed at a hospital or doctor’s office. This test actually measures the amount of HCG in your blood. It can measure amounts ranging from 5 mIU/mL to 2,000,000 mIU/mL or more. Quantitative testing is performed when it is not sufficient merely to know whether you are pregnant or not. Sometimes, your doctor will need to correlate your HCG levels with the progress of your pregnancy. Ask your doctor to explain the results of your quantitative pregnancy test.
Normal values
In non-pregnant women, both the qualitative urine and serum HCG tests will be negative. The quantitative HCG test will be less than 5 milliunits per milliliter. In a normal intrauterine pregnancy, the HCG should rise through the entire first trimester, and slowly fall thereafter.
What abnormal results mean
HCG levels that do not rise appropriately can indicate a problem with your pregnancy. Some problems this could suggest include miscarriages and ectopic (tubal) pregnancies. Extremely high levels can suggest twins. Your doctor will understand the significance of your HCG levels, and should explain them to you.