Originally Posted by Heavenly
You can't use the same urine sample for two tests. The negative is probably wrong. My sister did that (dipped more than one test in the same urine sample) and the first positive but all the rest were negative. My neice is 6.5 now. Try the more sensitive brand with a fresh urine sample.
Where did you hear this? I've got lots and lots of tests from single samples and I know many women online at fertility websites who commonly test with various brands of tests with one sample. There is nothing that would change the urine to make a false test and I've never heard of anyone having a problem until this.
Originally Posted by Citizenfong
Another possibility is that the first, supposedly less sensitive test, is actually MORE sensitive than the second one you bought.
What I've read is that some tests are marked to be sensitive to, say 100mIU, but will often pick up hCg in smaller quantities. I guess they are maybe only *consistant* at the 100mIU level, or for whatever reason the company does not choose to market them as more sensitive.
Now, this is true. Like I said in an earlier post, FRER claims to be sensitive to 15 or 20 mIU or whatever but I've heard of people getting a beta done the day that they got a faint positive and only have a beta level of 7 or something.
OP: If you're only 15 days past ovulation and you've used diluted urine or non-FMU, then a negative result is likely, especially with less sensitive tests.
If you're not concerned that you're late at this point, then don't worry yet (easier said than done, I know). If you're still thinking something is up, then use FMU with FRER, Answer or Equate. Good luck!