Waiting for a line to appear on a stick can take an eternity, but so often it’s the first way women realize they’re pregnant. The home pregnancy kit has been a staple on pharmacy shelves since the mid-‘70s, when e.p.t. — then branded the “Early Pregnancy Test,” but now marketed as the “Error Proof Test” — received FDA approval.

Those early home tests looked more like something out of a chemistry set, and took up to two hours to render a result. But the tests were fairly accurate, with a 97 percent accuracy rate for positive results and 80 percent for negative results.

Now, there are a variety of tests available on the market — and nearly all of them deliver results in minutes, not hours. Knowing how to use the test and what to do with the results is essential.

Do: Read the Directions

This seems obvious — but often, so does the method of using a home pregnancy test. But with so many models and types available on the market, it’s important to make sure you’re using it correctly.

Some tests feature a stick that you place directly into your urine stream, while others are dipped in a collection cup or use a dropper to place drops of urine on a certain part of the test. The amount of time it takes for the test to work also may vary. Make sure you understand what you should be doing for the most accurate reading. If you need help, nearly all home pregnancy tests will offer a support phone number on their packaging.

Don’t: Take One Too Soon

Home pregnancy tests work by detecting a hormone called human chorionic gonadotropin, or hCG, in your urine.

Some home pregnancy tests advertise that they’re more sensitive than others, providing results even before a missed period. But tests are generally more accurate if you wait until after the first day of your missed period, because the hCG levels in your urine increase with time.

Taking a test too early means there may not be enough hCG in your urine for the test to detect, leading to a false negative.

Do: Call Your Physician if the Result is Positive

While the home pregnancy test may indicate that you’re pregnant, a clinical blood test is the most accurate way to determine if you are, in fact, pregnant. And if you are, it’s important to begin receiving regular prenatal care to increase your chances for a safe and healthy delivery.

A quantitative hCG blood test can detect even trace amounts of the hormone in your blood. It also can give your medical provider an idea of how many weeks you are into your pregnancy.

A trusted obstetrics specialist can guide you through the next nine months, tell you what to expect from your body and share things you can do to improve your health and the health of your baby.

Don’t: Think That a Negative Result Means You’re Not Pregnant

Most pregnancy tests advertise that they’re up to 99 percent accurate — but this is under the best of circumstances. Even those that claim to provide the earliest results still note that they are more accurate if you wait until after you’ve missed a period.

The fact is, home pregnancy tests can result in false positives and false negatives alike. You may encounter a false positive if you’re on a medication that contains hCG, such as several treatments available for infertility.

False negatives can happen if you’ve taken the test too early after conception, when the levels of hCG are not yet detectable by the test, or if the fertilized egg has not yet implanted (the body doesn’t begin to make hCG until implantation occurs). According to the National Institutes of Health, up to 10 percent of women do not experience implantation until after the first day of a missed period.

A false negative can occur if you discard the test too soon as well. Research has shown that the most accurate results are available about 10 minutes after taking the test, which is often beyond the window of time that tests advertise.

Other factors related to the test itself can affect its accuracy. Pregnancy tests have expiration dates, and some are simply more accurate at detecting hCG or are easier to interpret.

If you’re not sure you can trust the results of the test, call your physician.

Here is another piece of advice: Many women who are trying to get pregnant find that they can order rudimentary pregnancy test strips at a lower cost online through sites like Amazon.com or even buy them at value retailers. While these may not be as accurate or easy to interpret as the fancier products available at the pharmacy or grocery store, they can still give you an early idea about a pregnancy at an affordable price. Plus, you can always use a more elaborate test to confirm the other test’s accuracy before contacting a healthcare provider.

It’s essential that you contact your healthcare provider as early as possible if you receive a positive test. Don’t take the value of regular prenatal care for granted; research has shown again and again that receiving medical care leading up to your delivery can result in healthier babies and mothers alike.

If you need an obstetrician, you can find one near you by calling Tanner’s 24-hour physician referral line at 770-214-CARE (2273) or by selecting the Find a Provider.

Tanner Healthcare for Women is a Tanner Medical Group practice located in Villa Rica. For more information, visit TannerHealthcareforWomen.org or call 770-812-3850.