Has anyone ever had a false positive pregnancy test?

[Gina A. 6]

Hi Everyone,

I am scheduled for surgery on 12/20/10 and have had all the pre-admission testing done last Monday. I had a long battery of tests including, blood work, X-Ray, EKG, meeting with the Anesthesiologist, etc etc. I also had to go to my PCP to get clearance from him. Since I take Coumadin for history of DVT's and Pulmonary Embolism, I needed a prescription for Lovenox (injectable blood thinner). I figured, I did everything right and I'm on my way.

Well, I get a call from my PCP on Wednesday saying that my pregnancy test came back false positive and I would need to repeat it. Needless to say, I was shocked and stressed because if I'm pregnant, that would be a major setback for me and the surgery. I have my blood work repeated on Thursday and get the same result. My PCP tells me to come back Monday (yesterday) to repeat yet again. I go get my blood work done, AGAIN, and yet again, I get the same result. My PCP said that it's fine, my blood work is strange, but, I'm not pregnant.

What would lead my blood test to continue to show up like that? Should I be concerned that it's another disease?

[BlackBerryJuice 349]

Did they do a blood or urine test both times? Blood tests are more accurate. Both can show up with false positives, but 2 in a row? The odds are almost 0. Did your PCP explain why s/he thinks you are not pregnant in spite of the positive pregnancy test? I'm no expert on this, but having covered ob-gyn in school already, I don't know how you can say someone's NOT pregnant when you've got 2 positive pregnancy tests - unless you do imaging.

[Dawn 16]

I've always been told that a false positive is a rare thing? I sure hope they figure out what is going on! Is there a possibility that you are?

[Gina A. 6]

All 3 tests were blood tests. I guess I should've mentioned a little background history. I have been diagnosed with Lupus about 14 years ago. I have severe Kidney disease as a result of the Lupus illness. I had been through numerous treatments, including chemo therapy to help with my Kidney disease, which has caused me to go into early menopause (I'm 33 years old). I hadn't had a period (TMI) in a couple of years. While I have the organs (uterus and ovaries) to bear a child, I never thought I would be able to get pregnant after all my issues.

That being said, I believe that my Lupus may have been the reason why the tests have come back false positive. Very strange to me, maybe I should get a second opinion?

[Becca 108]

I would get a second opinion or see if you can get an ultrasound to verify if you are pregnant or not. They usually run another pregnancy test right before surgery, so that could be a big problem on your surgery day if you don't clear it up. Good luck with everything!

[BlackBerryJuice 349]

I would get a second opinion or see if you can get an ultrasound to verify if you are pregnant or not. They usually run another pregnancy test right before surgery, so that could be a big problem on your surgery day if you don't clear it up. Good luck with everything!

I agree, ask for an ultrasound and ask why your PCP is so confident it's a false positive - rather than a legit positive. The pregnancy test measures beta-hCG, which is a hormone produced by the placenta. However, many tumors produce hormones, and some tumors, including some cancerous ones, will produce beta-hCG. So I think that even if your PCP is 100% sure you're not pregnant, you should get a more thorough work-up. I did a quick search on lupus and beta-hCG both on Google and a medical textbook database (Access Medicine) and I didn't see anything that said lupus would ever cause your beta-hCG to be positive on its own.

[BlackBerryJuice 349]

From Access Medicine, "Medical Oncology."

Phantom hCG Syndrome

Phantom hCG or phantom choriocarcinoma syndrome is also called pseudohypergonadotropinemia. It refers to persistent mild elevation of hCG when no true hCG or trophoblastic tissue is present. This often results in the patient being treated further by her physician during the follow-up period either after primary surgery for molar pregnancy or chemotherapy for metastatic disease. It is mentioned here because clinicians may encounter this problem during the follow-up period and should rule out this syndrome before deciding to label a patient as having persistent disease.

HCG is a glycoprotein whose two subunits, and , are held together by charge and hydrophobic interactions. Over 40 different professional laboratory tests are available for assaying the level of serum hCG. Most of these work through the multiantibody "sandwich assay," using the labeled-enzyme or chemoimmunoassay (RIA) method developed in the 1950s. The mechanism by which heterophilic antibodies cause false-positive results relates to the nature of this immunometric assay. One antibody, commonly a mouse monoclonal immunoglobulin (IgG), immobilizes hCG by binding one site on the molecule; a second antibody, commonly a polyclonal antibody labeled with an enzyme or chemiluminescent agent, marks the first antibody. Heterophilic antibodies usually bind the assay of IgG at sites common to humans and other species. They are bivalent and therefore link the capture and tracer antibodies, mimicking hCG immunoactivity. Binding of human antibodies to mouse IgG is the most common form of interference. The positivity of this test, however, is not correlated with positivity in the urine. Therefore a simple urine hCG test can support or refute a phantom hCG test result. If both the urine test and the serum test results are positive, searching for occult disease is prudent. If the urine test is negative, assuming that no clear radiologic sites of disease are identified, different assay systems can then be used to confirm the first serum result (82). It is recommended that the serum be tested by a reference lab in these cases.

Phantom hCG reemphasizes the clinical dilemma that arises when patient care is based primarily on laboratory data. It is the clinician's responsibility to interpret test results with caution. Unfortunately, the prevalence of false-positive hCG results is not known. In one series of healthy individuals, it has been found to be 3.4% (<a href="http://www.accessmedicine.com.login.ezproxy.library.ualberta.ca/content.aspx?aID=2795043#2795043" target="_parent">83).

[MommyTawnie 3]

I must agree with the other answers. To get 3 false pregnancy test in a row is rather strange. False postives are very rare where blood work is involved. Call your pcp and see if they could do an ultrasound to insure all 3 blood test were indeed false positives. While pregnancy would be a set back would it be a bad thing with your history to have such a miracle happen? Clearance from your pcp to show that it is indeed false positives you are getting would be ideal for day of surgery. You don't want to get there and be told they need to wait a bit to see what's going on with the blood work. Best of Luck to you in any situation!!