Taking a hyrdometer reading

[badgerdan]

Hi, i forgot to take a reading before putting my beer in a keg, it's now getting carbed up so can't take any out but i did have some in my syphon, but when i took a reading from that (using my refractometer) it came out as 1.035???

The thing had been very active for a good few days and always in a temp controlled cupboard so am wondering whether if the last dregs of beer from my tub had lots of extra yeast from the bottom in it and hence making it a wrong reading or whether this won't make a difference?