Home tests positive Clinic test negative

I have had four miscarriages with one live birth between the third and fourth miscarriage.  Since my last miscarriage/D&C I have felt like things are not the same as before.

I am a person who has always had their menstrual cycle at 28 days.  There has never been a deviation.  Since the D&C my cycle has fluctuated by a few days on both sides.  In the last few months I have had some major concerns with my cycle.  Last month I didn't get my cycle so I took a home pregnancy test.  It came back positive. I took another one to make sure the next day it was also positive.  I waited a few days and then went in for a blood test at the clinic.  That test came back negative.  I got my cycle about 5 days late.

This month again my cycle didn't start.  I took a pregnancy test on Saturday (my 28th day).  The test was positive.  I took another one on Monday and it was positive.  I waited until Thursday to go in for a blood test.  That was negative.  I took another test at home and that was positive.  What is going on?  My doctor has me on prog. from day 16 until my cycle starts because they can find no other reasons for my miscarriages.  I also have had a sharp pain on the left side of my abdomin (abdomen).  I'm really confused and need some direction.  Of course it takes so long to get a doctor's appointment so I'm unable to see him for a few weeks yet.  Why would the home pregnancy test be coming back positive when the clinic test is negative?  Why do I have a pain on the left side of my abdomin (abdomen)?Thanks for taking your time to answer my questions.

[nurse12hr]

It seems to me we had a post a while back from someone in the same predicament--I did some research on the net about it, and I think there IS some real medical explaination, but I don't have time to look into it right now.  

Something like there is some real syndrome that causes an HCG like substance to be excreted in the urine, but not in the blood.  So the urine test is fooled into thinking it is positive, and the blood test won't detect it.  I don't recall the specifics, but I will definately get back to you on it.  It was interesting.

I am sorry you are having some a confusing time with all this.  Sending hugs.

[nurse12hr]

Laverne
Darn it all, I got interested and had to look it up right now.  Here is what I found:

Causes of False Positive Pregnancy Tests

Evaporation Line - most common
Often when a test is read beyond the specified time, as the urine evaporates it leaves a faint, colorless line.  When a line is seen after the time on the box, look for color, the same color the control line is. If you see color, it is more likely a true positive, but test again in 2 days.   This gives a pregnant body time to double the hCG and you should get a darker line, if indeed pg.  Also, avoid reading the test after the time shown on the box, and try to use first morning urine.
The test itself
Some tests are just infamous for false positives.  The old Equate (white cap) was one of them.

Elevated Levels of LH - the ovulation inducing hormone
LH is chemically similar to hCG1, and especially in women with PCOS, elevated levels of LH can cause a false positive.

Fertility treatments
If you are receiving shots of Gonadotropins with ovulation, chances are if you take a test before you miss your period it will be positive either way.  Talk to your doctor about when you can test.  On a side note, these shots also give very convincing symptoms.

Chemical Pregnancy, Early Miscarriage
Sometimes when an egg gets fertilized but doesn't implant well and is expelled, it can cause slightly raised levels of hCG, which can be picked up with the more sensitive tests.  Or the egg implants, but is lost near the time your period is due.

Some Drugs
Methadone, chlordiazepoxide, or promethazine may cause false positive pregnancy tests.2

Rare reactions:

Mouse hCG antibodies are used on the test line portion of the test, some women's hCG may not react correctly with this, giving either a false positive or a false negative.3

Some women have a low level of hCG-like material circulating at all times, this may cause a false positive in rare cases, especially in very sensitive tests.3

Some tumors may also cause false positives.3

1Source: http://courses.washington.edu/pwpbw/preg/sld003.htm University of Washington

2Source: http://epregnancy.com/info/preconception/ptest-results.htm Myria Network, ePregnancy

3Source: http://www.mcl.tulane.edu/classware/pathology/medical_pathology/prenatal/03pregnancy.html Tulane School of Medicine

I believe the post we had a long time ago, was attributed to the womans antigens reacting falsely to the HCG in the urine test.  I just can't remember what her doctor told her about it.  

I would see your doctor specifically to talk about this issue.

[Laverne]

Thanks Christie for the information. It gives me a little information before I can get into my doctor in 2 weeks.

[38weeks]

Hey, if you read the box of a home  pregnancy test it says something like it can say postiave and your hcp leavel is high cus your pregnant and it also says that tumors can cause a home pregnancy test to show positave I don't mean to scare you but my sister inlaw had a tumor on her overies and she thought she was pregnant and the later went for an ultrasound and found a tumor so you need to get checked asap...

[Lisadengel]

38 weeks,

Why are you scaring her like that?  That is completely unnecessary.  I have seen a few posts where you imply or say things that could send the reader running off to her doctor.  People's nerves are already frayed on this board to some degree and they don't need someone coming in and scaring them half to death about tumors and such.

Please try to restrain yourself.  There are false positives all the time, and I would think that if her doctor is aware that there are positives at home and negatives in the office and something were truly the matter, he or she would have already talked to her.

Really, this is just ridiculous.