Different HPT's, different results?

[gurnz]

I am on CD31 (usually about 28-29) and I have tried testing 4 times now with the same brand and all of them have been negative. I do feel pregnant, but of course want to confirm it. If a try another brand do you think I might get a BFP or won't it matter if it's too early?

[monnie]

What you need to look out for is the number of mIU/ml the pregnancy test is measuring...

The lower the mIU/ml, the more sensitive the test...and therefore the earlier you can test!

Some tests are 10 mIU/ml...most are around 25 mIU/ml...some are more like 50 mIU/ml

Here's what wikipedia says:

All commercially available tests for pregnancy look for the presence of the beta subunit of hCG or human chorionic gonadotropin in the blood or urine. They are usually performed after a missed menstruation or 2-3 weeks after ovulation.
hCG can be detected in urine or blood after implantation, which occurs six to twelve days after fertilization.[1] Some home pregnancy tests claim to detect hCG as early as 4 days before the next expected period. Whether that statement is accurate for an individual woman depends on the length of her luteal phase and on how soon that individual embryo implanted. Quantitative blood (serum beta) tests can detect hCG levels as low as 1 mIU/mL, while urine tests have published detection thresholds between 20 and 100 mIU/mL, depending on the brand.[2] Qualitative blood tests generally have a threshold of 25 mIU/mL, and so are less sensitive than some available home pregnancy tests.

The really sensitive ones can be ordered through lullaby conceptions (10mIU)

Good luck!!!

[Tobily]

Fortel Ultra is available at Woolies/Safeway and it measures 10mlU.
I have had success with these but have also heard some complaints about false positives. However I tend to think that because they are so sensitive they tend to detect very early pregnancies which fail early hence more "false" positives.
Worth a try I have never had a problem with them.