HgB-F is Fetal ...
HgB-f stands for Fetal Hemoglobin.
Usually this is replaced by adult hemoglobins by the age of six months. If there is persistent HgB-f you may have a mild blood dyscrasia. After all you are 38 years old are just finding out about this now. Some medications may induce the production of HgB-as well. So talk to your doctor. Unless you are pregnant, in which case you might ask your Obstetrician.