You (or someone else in your household) probably spend a decent amount of time doing laundry, especially if you have kids. You want to know, of course, that your detergent is getting everything as clean as possible, and that it won't cause skin irritation or allergic reactions. Once you find one that works, you'll probably stick with that tried-and-true brand for years -- if it ain't broke, after all, there's probably no need to fix it.
But you might unexpectedly get the urge to change one day. Maybe one of your kids has suddenly developed a rash, or perhaps you just came across a great deal on a new brand. How do you know if this new detergent is going to do a better job? Before you wash a full load of your kids' clothes in it, should you test its cleaning power and make sure it won't cause rashes?
Well, probably not. Testing does seem like a great way to ensure you bought the right product, but it isn't foolproof. A cleaning-ability experiment seems fairly straightforward, but what you might think is a detergent problem could actually be an issue with your washer or water type. There are so many variables that come into play.
An allergy test could also be problematic. How would you conduct it -- dab some of the detergent onto your skin, or have your kids wear clothes that have been washed in it? If there are allergic reactions, the problem might not be with the detergent itself but in the amount you used. If you're using too much, there could be irritating residue in your clothes, sheets and towels. It would be pretty difficult to pin down the culprit.
And contrary to what you might have heard, it isn't all that common for laundry detergent to cause skin allergies. In a 2010 study published in the Journal of the American Academy of Dermatology, allergy patch tests with detergent were administered to 738 people who had complained of allergic contact dermatitis symptoms. Less than 1 percent of them reacted to the laundry detergent.
But some people do have allergic reactions to detergent, and the culprits are often fragrances, nickel and potassium dichromate. So if you have very sensitive skin or suspect a detergent allergy, just read the bottles and avoid products with certain ingredients -- there are plenty of fragrance- and dye-free detergents out there. That's a whole lot easier (and cheaper) than using the test method.
So, in a word, our answer is no: You don't have to test detergent before using it. But be an educated consumer -- find out the right detergent (and use the right amount) for your washer, and stay away from products with common irritants.