Unexpected hCG Disappearance: Understanding Potential Causes & Next Steps

Question
I had gone to My Obgyn after my period was a week late. I had an ectopic pregnancy just over a year ago. So wanted to be careful and get checked properly. I gave a urine sample and then a nurse came to the exam room and told it was positive and to get ready to see the Dr. Then 10 minutes later another woman came through who had performed the test, telling me that the line she had saw had disappeared when she went back to it and apologised. I was very distressed. They have done a blood test I have to wait for. Can you tell me is this possible for a positive result to just disappear like that? i ithough there was no such thing as a false positive, let alone a disappearing straight away one. Now I seem to be spotting a little and having sharp pains. Either way, this confusion over the disappearing line is baffling me. Your advice or answers are most appreciated. Many thanks.

Answer
Dear Jacqueline

No it is abnormal for such thing to happen. However, a positive test usually gives a dark line..faint lines can occur and these may be misinterpreted as positive. May be the person who read it initially did not have enough experience to judge. I have no other clue.

Good Luck