Are $1 pregnancy tests reliable?
SAN FRANCISCO (KGO) -- Would you trust the results of a $1 pregnancy test? There are inexpensive brands now available at discount stores and online. So how reliable are they? Experts say their effectiveness depends on a number of factors.
"If I thought about it, 'maybe I'm pregnant.' So I'd go get one, and then it could be five a week," said Grasso.
Those tests typically cost $10 to $15, but they can be much cheaper. They can be as low as $1 for brands like New Choice and Baby Brand, sold at discount stores like Dollar Tree and Dollar General. Many women like Grasso see them as a bargain.
"I feel like it's the same thing, and it's also much more affordable," said Grasso.
But are the tests reliable? Audrey Koh, M.D., is an obstetrician at California Pacific Medical Center in San Francisco. She says it first helps to understand that all the tests look for a hormone called HCG, or human chorionic gonadotropin, which is produced during pregnancy.
"But the difference between the tests is that some have an ability to pick up a lower level of HCG than other tests," said Koh.
She says the sensitivity comes into play in the earliest stages of pregnancy, before the fertilized egg has attached to the wall of the uterus. That process is accompanied by the release of HCG, which the tests can then detect with various degrees of sensitivity.
"None of the home tests that you can get over the counter will pick up an HCG level of one or two. Unlike blood pregnancy tests which will pick up minute levels of HCG," said Koh.
But there are differences. Koh says a top-of-line at home test can pick a reading as low as 5.5, measured in international units. Other premium brands pick up 20 units and all tests are designed to detect a minimum of 50 units. Since HCG levels typically double every 72 hours. The difference could be a matter of days to a week, before a less sensitive test registers a true positive.
"Probably the best advice in terms of when to check for pregnancy would be to wait at least one day past when the woman is expecting her period," said Koh.
A that point, the FDA approved tests generally boast accuracy in the high 90 percent range. For many women it may come down to a question of economics versus timing.
"A lot of people probably are skeptical about it, but there's a generic brand for everything," said Grasso.
Koh says it's also important to follow the instructions carefully. Some tests require a certain amount of time to produce a reading, while others may fade quickly if they are read too late.
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