I am approx. 6 weeks i had my first hcg test it was a normal 3,000 however has a retest 92 hours later and it was only 4888 should i be concerned ?

Yes: what did your OB say? BHCG should double every 72 hours and a Progesterone level should have been drawn also as a low one is worrisome,a high one reassuring, the BHCG needs to be repeated in 72hrs from the last one, to make to see if it doubles but the 4888 is worrisome and the BHCG should be higher at 6 weeks and should be able to see a fetus with htbeat at 6 /12 weeks