Modern Family Living :: The online magazine for the modern family living and lifestyle

Home

Departments

Parenting

Home Pregnancy Test Kits: Accurate and Reliable?

E-mail

Written by Franco E. Santos

Pregnancy and Motherhood at Modern Family Living .com Not too long ago, if you suspected that you are pregnant and wanted to know for sure, it meant that you would have to consult with a doctor, an obstetrician or other medical practitioner. It also meant that you would have to submit to either a blood test or a urine test. The sample is then sent to a laboratory for analysis to detect the presence of certain hormones. After you have submitted your blood or urine sample and while it is being analyzed, you then sit at home to wait for a call for confirmation. Oftentimes, the call may not come for a number of days or even weeks. Needless to say, back then finding out whether you are pregnant or not was more complicated and literally required a medical degree.

All that was during your mother's time. With present day's technology and medical advances, there are a number of choices of over-the-counter home pregnancy test kits. These over-the-counter home pregnancy test kits are available at your local drug store or the nearest Rite-Aid, Walmart, and other chain stores. The greatest benefit of today's most widely used pregnancy test -- that of the home pregnancy test kits -- vis a vis the old fashioned, albeit more accurate than the store bought version, laboratory-analyzed test is the instant gratification of knowing. No need to stay awake at night wondering "what if?" The question is: how accurate are these over-the-counter home pregnancy tests? The answer is, it depends. The reliability and accuracy of home pregnancy test kits can be affected by a number of things.

In a nutshell, over-the-counter pregnancy tests from a local drug store and tests done by professional medical laboratories work pretty much the same way. Both tests examine the presence and level of a hormone called Human Chorionic Gonadotropin (hCG) which is produced by the embryo soon after conception and is secreted in the blood or urine. Blood samples are more dependable than urine samples, but for most the process of extracting blood sample is less than pleasant. Because of the unpleasantness, most over-the-counter home pregnancy test kits analyze urine samples.

The value of an over-the-counter home pregnancy test is in its readability and sensitivity.

Readability, or ease of interpretation, is a personal matter. Over-the-counter home pregnancy tests differ in the way they present the result. Some kits may be easier for some people to read and understand than others. Pregnancy test result can be presented by matching a color strip, numerical value, while others simply say "pregnant" or "not pregnant." Which you choose depends largely on personal taste. (While waiting for the result of a pregnancy test with the aid of readily available over-the-counter option is no longer a consideration, waiting too long to read the result of the test may in fact render the result unreliable.)

Present-day over-the-counter home pregnancy kits from many major manufacturers are dependable. However, False negatives and false positives aren't completely absent, however comprising fewer than 5% of cases. As tests become increasingly sensitive, the amount of false positives tend to go up. Some of the possible causes for the false positives include elevated levels of hCG present in women who have recently given birth or suffered from a miscarriage even though they are no longer pregnant. Also, an unknown number of medications can cause the level of hCG to rise.

On the other hand, just as there are factors that can raise the level of hCG, there are factors that can lower it as well, including medications. The lower level reading can result in a false negative.

Some home pregnancy tests can measure hCG levels as low as 25 mIU/ml (milli International Units per milliliter). The abbreviated unit after the number is complicated, but not important to the home consumer. Just look at the sensitivity rating of the test and compare. To appropriately minimize false positives, tests can be configured not to give a 'Pregnant' reading until higher levels are reached. Several quantify levels at 50 mIU/ml or even at or above 100 mIU/ml.

But, to raise the level of sensitivity also raises two dilemmas:

One, if the test detects hCG only at higher levels. You have to be pregnant longer before the body builds up to that level. That reduces the value of a home test, many of which are labeled EPT (EARLY Pregnancy Test) for a reason. The other potential problem is closely related. It can introduce false negatives, you really are pregnant, but the test tells you that you are not.

The problem is that no over-the-counter home pregnancy test measures pregnancy directly. The only means to accurately measure the level of hCG is to analyze the potential mother's blood and the implantation of the embryo into the womb, a process that thus far, cannot be conducted at home.

For most women, the shortcomings of over-the-counter home pregnancy test kits are a minor consideration. A home pregnancy test is a great convenience. Besides, many HPTs come with multiple strips. Test once, then test again a few days later. If you get the same result, the odds are much higher that the test is valid. However, as soon as a positive test result is achieved, a complete test should be conducted by a doctor.

It goes without saying that a great part of any test's accuracy is in the ability of the test taker to follow the instructions. Home pregnancy test kits are no different. Follow the instructions carefully and, after you have tested a few times, you can be confident that the test is telling you the truth, in 95% or more of cases. Those are pretty good odds, all things considered.

Franco Espeleta Santos is a graduate student working on his Master of Arts degree in Psychology with emphasis on Marriage and Family Therapy. Visit his blog at FrancoSantos.com