DEAR DOCTOR K: I'm a 31-year-old woman, and I try to donate blood every couple of months, but the last time I tried, I was turned away because my hemoglobin was too low. What does that mean? And what can I do about it?
DEAR READER: That's terrific that you are a regular blood donor. The American Red Cross says that one pint of blood -- roughly the amount collected during a donation -- can treat an average of three people who need blood. And that treatment can save lives.