Home Pregnancy Tests 101

NOTE: Pregnancy Test Strips Instructions are specific to FDA Approved 20 mIU/ml/hCG tests. They are re-published here as a single example of hCG urine pregnancy test instructions. These instructions should not be generalized to other tests - or tests with different hCG sensitivity levels (early-detection threshold).

How to get the Most Accurate Results:
Testing Directions, Use, and Best Procedures

Home pregnancy tests [1] detect, and to some degree measure, human chorionic gonadotropin (a hormone) in urine. Women produce this hormone in elevated quantities when they fall pregnant. Human chorionic gonadotropin - or hCG as it is referred to - begins to appear in high quantities once the fertilized egg or embryo implants to the uterine wall (or the tissue lining of the womb).

Following pregnancy, the hCG hormone increases very quickly, with the quantity produced doubling approximately every two days. According to the specifications of the test manufacturers, hCG reaches the 20 mIU/ml threshold at around 7 to 10 days past ovulation. This is when you can begin testing. Remember: A negative result at 7-10 DPO does not rule out the possibility of pregnancy, as hCG develops at different rates for different women, and different urine samples may exhibit differing volumes of the hCG hormone.

While ovulation tests [2] will show you a qualitative result in which you must compare the intensity between a test line and a control line, with a pregnancy test [1] you simply look for the presence of the test line. The control line is there to indicate that the test is valid, that correct procedure was followed, and that enough urine was allowed to move up through the testing components. Therefore, a faint color band - or faint test line - is indicative of a positive result (as long as all instructions are followed).

To optimize use of the tests, you may wish to use first morning urine - or your first urine of the day after sleeping all night - because it will contain the highest concentrated amount of the hormone. You can test later in the day, of course, but do note that you should not drink a great deal of liquids or urinate too often. Hold your urine for a few hours, or as long as possible, before doing the test. Again, if you receive a negative early on while you are testing, it may not totally rule out the possibility of being pregnant. Follow up tests are always recommended.

Principles of the Test
The test reagent is exposed to urine, allowing urine to migrate through the absorbent device. The labeled antibody-dye conjugate binds to the hCG in the specimen forming an antibody-antigen complex. This complex binds to the anti-hCG antibody in the test zone and produces a purple color band (test line) when the hCG concentration is equal to or greater than 20 mIU/ml. In the absence of hCG, no band is formed in the test zone. The reaction mixture continues flowing through the absorbent device past the test and control zone - producing a second purple color band in the control zone that demonstrates that the test kit is functioning correctly.

Types of Tests
There are two basic test types - the strip and the midstream. Instructions for the strip test is below. Click here [3] for info on the the handheld pregnancy test (which is exposed to the urine stream directly).

Urine Collection 1. First morning urine, as noted above, is the best sample for performing the test. However, any urine specimen may be used (though urine should be held at least two or three hours before specimen collection to prevent dilution of the sample). 2. Collect the urine specimen in a container.

Test Procedure 1. Remove the test from the airtight package. 2. Holding the strip vertically, carefully dip it into the specimen. Do not immerse the strip past the max line. 3. Remove the strip after 4 to 5 seconds and lay the strip flat on a clean, dry, non-absorbent surface.

Interpretation of Results 1. Wait for colored bands to appear. Depending on the concentration of hCG in the test specimen, positive results may be observed in as little as 60 seconds. 2. However, to confirm negative results, the complete reaction time of 5 minutes is required. Interpret the test results at 5 minutes. NOTE: Do not read results after the 5 minute test reaction time.

Interpretation of Results

POSITIVE Result for Pregnancy: Distinct color bands appear on the control and test regions. Presence of both test line and control line indicate that you are pregnant. The color intensity of the test bands may vary since different stages of pregnancy have different concentrations of hCG hormone.

NEGATIVE Result for Pregnancy: Only one color band appears on the control region. No apparent band on the test region. This indicates that no pregnancy has been detected. does not contain a detectable level of hCG and should be interpreted as a negative result.

Standardization

The Pregnancy Urine Test will detect hCG concentrations of 20 mIU/ml or greater. This sensitivity level has been confirmed with internal hCG standards in urine, calibrated against the World Health Organization First International Standard. Do not use after the expiration date imprinted on the test kit package. Dispose of all tests in a proper (biohazard) container.

• Pregnancy Tests

> Pregnancy Test Strips [4]
> Pregnancy Midstream Tests [3]

• Ovulation Tests

> Ovulation Test Strips [5]
> Ovulation Midstream Test [6]