A: The earliest you can get a positive result on the most sensitive pregnancy tests is seven days after ovulation. Implantation needs to occur before hCG is produced, and that generally happens between 6-12 days post ovulation, usually by 10 days after. For this reason, it makes economical sense to wait until 10-12 days after ovulation, but even then a significant percentage of women who are pregnant will still show a negative result. Many people won't have a positive HPT until the first day of a missed period or even a few days later.

Q: How accurate are home pregnancy tests on the first day of a missed period?

A: The highest possible screening sensitivity for an hCG-based pregnancy test (20-25 mIU/ml) conducted on the first day of a missed period is 90 percent, as 10 percent of women may not have implanted yet. With the same test, one week after the first day of the missed period the accuracy increases to 97 percent.

Q: What time of the day can I use the test?

Because home pregnancy tests detect hCG, diluted urine samples (from drinking large quantities of water) aren't recommended. It is best to collect urine samples containing the highest presence of the hCG hormone. First morning urine is the ideal sample as it contains the most concentrated presence of hCG. Otherwise, waiting several hours (4-5 minimum) is considered sufficient duration for an HPT.

Q: How do I use the test?

A: There are two types of HPT's -- test strips and midstream tests. For test strips, immerse the strip into the urine sample with the arrow end pointing towards the urine. Do not immerse past the MAX (Marker Line). Take the strip out after 3 seconds and lay the strip flat on a clean, dry, non-absorbent surface. 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 40 seconds. However, to confirm negative results, the complete reaction time of 5 minutes is required. Do not read results after the 5 minute reaction time.

With the pregnancy midstream test, hold by the handle so the absorbent tip, located on the bottom, is facing down. With the handle side of the test stick facing you and the twin absorbent tip pointing in a downward direction, hold the test stick in your stream of urine (and hold it for at least six seconds so that adequate urine contacts the absorbent end). Seal the absorbent windows with the cap. In 2 to 5 minutes, a rose-pink color band (control band) will appear in the window to show that the test is complete. Q: How long do I wait to read the test?

A: A positive result can be seen as quickly as 40 seconds. You should not rely on any positive result that does not show up within the time limit (usually 5 minutes) stated in the test instructions. All pregnancy test brands have the possibility of displaying an evaporation line.

Q: How does a positive result look?

A: You should check the instructions that came with the HPT as there are some differences between the tests. Most of the tests have two windows -- one that tells you the test has been performed correctly (control), and one that gives you the positive or negative result. In the result window, the tests usually give a line or a plus. Any line, no matter how faint is considered a positive result. The color intensity of the test bands may vary since different stages of pregnancy have different concentrations of hCG hormone.

Examples of Line Tests
negative result	positive results

Examples of Plus/Minus Tests
negative result	positive results

Examples of Digital Tests
negative result	positive result

Q: Is a faint line still a positive?

If the test was read within the time limit, a positive line, no matter how varied the line colors, should be considered a positive result. All HPTs should be read within the time mentioned in the instructions and then thrown out to avoid confusion over evaporation lines.

Q: What if the test is negative after the 5 minute reaction time, but becomes positive after an hour?