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.
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.
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.