What does a "doubtful positive" result mean?

Does anyone know what a non-positive result for marijuana means?

I have had three positive pregnancy tests, a doctor confirmed positive test.. but when I went to have my ultrasound they said...

I dont know if im pregnant or not how im also scaird to take a test I took one 3 weeks ago and the test showed a line in one ...

Not a nice thing to ask but bugging me. I seem to get different results from my douche some days, is there a trick to it? Wh...

can you get a faint positive pregnancy test, then a negitive test result, start spotting and still be pregnant?

I didnt have my period last month. I was spotting for a week though.what does this mean?

I took 3 pregnancy tests a few days ago all were positive but went to the doctors and have a bladder infection would I still ...

yeah like a lugied and it was a brownish yellow what dose that mean

does brownish red discharge mean your prego? or is it just a rare early symptom of your period?

I recently had a MRI and the results just got in. So I went to the doctor and he said that there were some cracks in the bone...