http://www.911restorationinc.com/blog/water-damage/how-mold-test-kit-helps-you/

Your home is your place of safety and comfort for you and your whole family. However, as a property owner, it's essential that you maintain your home as clean and safe as possible to ensurey your health and the health of your loved ones. Even if you take care of your home, there are some issues that can arrise like water damage and mold infestation that are out of your control.
If you begin to notice health issues like insomnia, difficulty breathing, and allergic reactions, you may be experiencing symptoms of mold exposure. If you notice black or green discolarations on your walls, you should contact a professional immediately.