If your wondering about the color of the Ketosis strip, take a look at this and relax.

Ketosis is an indicator used at The Atkins Center as a marker for whether a person is staying on the diet. Ketones are formed when the body breaks down fat. If you are restricting the amount of carbohydrates you eat, then the body's preferred source of energy is used for metabolism. There are many reasons why a person's ketone test strip would be varying shades of purple. Each dieter's metabolism level is different and therefore will turn the sticks a varying degree of purple. In addition, the time of the day, whether or not you exercise, and what you had at your last meal will all affect the ketone test strips. It also does not necessarily matter whether you are turning the strips a dark or light color. The important thing is you are in ketosis and are burning fat. However, keep in mind that every individual's metabolism is different, and as a result, there are patients at the Center who never even get into ketosis, yet lose all the weight they want. In summary, don't worry about the exact level of ketosis you will find on the strip. The important thing is to worry about the restrictions of the diet, how your clothes are fitting and what the scale says. Because of this, I sometimes do not even use the strips, nor do I encourage you to weigh yourself every day. This should be done once per week. Don't make the common mistake of eating less fat to get into ketosis; the opposite is actually true.

Here's the site I got this from:

http://www.deepdiscountnutrition.com/whatshadofpu.html