My husband gets them when his red count is low, but guess they can only give once a week unlike the white count you can get shots every day for those low counts. Stans red counts are never within normal range and they don't worry about it too much. They are just a bit low all the time, but not extremely low. (just a bit below the normal range) Our doctor explained to us that each person is different and how they respond to the shots is up to the person's body and some people have great blood counts and others are shot after the first round of chemo and fight the entire time during chemo with the counts having to cancel chemo after chemo. Luckily, Stan usually has been good in that area and not had to cancel too many chemos, other than the last couple of weeks due to being weak and having thrush.
I hope some of that helps, but probably looking it up on the Internet might help. Good luck finding the information you need...oh, also ask the doctor.