I may not understand what is meant by "hemogloobins".. I assumed "hemoglobin" or in effect the red blood cell count.
I now understand you to say the finger prick yields blood, but the hemoglobin is low This could result in a general feeling of fatigue and even some yellowing (if white race) of the skin in severe cases - a hemoglobin well below 10. I was as low as six once an it turned my skin a yellowish color - I looked sick. This made be break a number of years on not going to the doctor. I had insurance too : ) I had a lot of tests and nothing other than an iron deficiency was found. An over-the-counter supplement fixed that. That was over 15 years ago and I took Iron sup for only a couple of months. No idea what caused the problem, but it hasn't returned. I now gete a physical exam every year including the "full" blood test. My hemoglobin runs between 13-15 a very healthy level.
No I do not play the guitar or have any callouses on my hand. I do indeed think I may have poor circulation as my arms and legs "fall asleep" frequently if I am leaning on them and at other times. Would bad blood ciruclation cause hemoglobins to go undetected? A couple of months ago I was having a strange feeling in my left arm like a pinched nerve almost. It didn't really hurt but was annoying and throbbing keeping me from sleeping. Not sure if that has anything to do with it or not.
Do you play the guitar or any other activity that would make your left hand finger tips hared/calloused? If yes, that's my guess...but the nurse would surely notice that.
If you can't come up with any other reason and you have no symptoms, e.g., tingling on the left side of your body - especially left arm/hand, I'd ask my primary care to check my circulation. I have had that done for my legs a couple of times because of what I call "tired legs". The circulation check okay, so guess I just have (old) tired legs.