Thank you for asking the query at DoctorSpring.
RBC count of 6.4 is not alarming. This can be a normal finding. If you smoke, or live in a high altitude or if you were dehydrated at the times of testing then this can be high. If you are not having any symptoms and if your all other blood tests (Complete Blood count) is normal, then there is nothing to worry.
Hope this helps.
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