DEAR DR. ROACH: A year ago, I was diagnosed with iron deficiency anemia. A colonoscopy found no problems. An endoscopy found a small raw spot on my stomach lining; it was not bleeding. My iron count was 7. Two months earlier it was 102. I was told to take an iron supplement twice a day. Now a year later, it is back up to 78. Up until my diagnosis, I had been donating one unit of blood approximately every eight weeks. My doctor told me to stop the blood donations, which I have done. I also eat more iron-rich foods than I used to. My blood type is 0+, and the blood centers are asking for donations. At what point will it be OK for me to donate again? — A.H.

ANSWER: I admire your dedication to providing a critical resource for your neighbors and your community. The COVID-19 pandemic decreased the amount of blood donation, and many blood banks are asking their regular donors to come back. I’m glad you are also keeping your own health in mind.

The normal range of iron in the blood is approximately 60 to 150, so you are now in the normal range. Blood banks generally do not evaluate iron levels, but rather the red blood cell levels, particularly the hemoglobin level. Most blood banks will not accept blood from a woman below 12.5 or a man below 13. When your hemoglobin level is above this amount, it is considered safe for most people to donate blood. Your own doctor’s recommendation is of the most importance, as they know your medical conditions better than anyone else.

I recommend you and your doctor remain vigilant about the underlying reason for the iron deficiency anemia. It might be that the regular blood donations reduced your iron stores faster than your iron consumption could replace them. The normal colonoscopy result is reassuring, as blood loss in the digestive system is troubling. However, even a colonoscopy can occasionally miss something, and there are other places along your gastrointestinal tract (plus a few additional sources of potential iron loss) that it may be worth another look should you become anemic (low hemoglobin level) again.

Finally, some people can develop an inability to absorb iron. Crohn’s disease and celiac disease are two of the most common reasons.

DEAR DR. ROACH: Has any research been done that shows a correlation between the severity of one’s chickenpox and the chance of developing shingles? My sister was covered head to toe with chickenpox, while I only had one mark. She developed shingles when she was in her 60s. She never got the vaccine. I received both vaccines and have not developed shingles, so far. — S.D.
ANSWER: Chickenpox and shingles are both caused by the varicella-zoster virus. Chickenpox is the original infection, and shingles is a reactivation of the disease years or decades later.

I couldn’t find any research linking severity of chickenpox to the risk of developing shingles, but I don’t think there is likely to be a connection. The severity of shingles is related to the age of a person when they get it, with older people much more likely to get severe pain.

Children who received the chickenpox vaccine (made with a weakened strain) are less likely to develop shingles than those who had an active chickenpox infection. The shingles vaccine, particularly the new two-dose Shingrix brand, is very effective at preventing shingles and also of preventing the complication of persistent pain after the disease.

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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Dr., Orlando, FL 32803.

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