SJ,
This is not a Reiki protection, but it is a basic protection that works 100% of the time and it is very simple to do.
Close your eyes for a brief moment, take a deep breath and let it out slowly, imagine yourself inside of a light bulb, completely surround by this brilliant white light. Next, surround the other person with this same white light.
White hold the full spectrum of colors and nothing negative can pass through it. If anything enter your white light field it turns from negative to positive. We use it for everything! Always white light yourself first, then white light your subject or person next.
I taught this back in my Psychic classes back in the 80"s and it never fails!!!!!
Sometimes when I white ligth someone, I get carried away and end up white light the country, then the world, then the universe and on and on.....

Also, I just white lighted your sister, i think she needs it
Hope this helps

Aloha
Keoi