Hi Georgette - I am a little confused about what you are saying.

FMU is the wee you do after you get up in the morning. This is obviously more concentrated as it has sat in your bladder all night. Because it is concentrated you will get a more accurate hcg detection.

If you hold your urine (don't go to the toilet) for four hours during the day and you have limited your fluid intake you will also get a concentrated urine sample albeit not quite as concentrated as fmu.

I hope that helps some. Are you in Australia? It is unusual that you can't get a quantitative hcg level done. Wishing you lots of luck for a