actually yes, it CAN trigger a false negative so can mouse/ goat handling . I have the reason too..
Causes: False positive increased serum hCG[br>"022 Causes[br>Heterophilic antibody (most common)[br>Human anti-mouse antibody (HAMA)[br>Nonspecific protein-binding hCG-like substances[br>Red Blood Cell interference[br>Marijuana use[br>Hypogonadism[br>"022 Confirmation methods in non-pregnant conditions[br>Qualitative urine hCG[br>Serum hCG by different immunoassay method[br>Serial dilutions of serum hCG sample
http://www.conceptiontechnologies.com/images/ReferencesPDFs/assurehcg_cassette.pdf": for mice : To make the Home Pregnancy Test, mice are injected with purified hCH (a foreign protein - an antigen - to mice), and a few weeks later the antibodies that they made to hCH arere isolated.Home Pregnancy Tests use 3 different types of antibodies: Two from mice and one from goats. The first antibody molecules are placed in the papery material in the test strip (where the urine sample is applied). When a urine sample is applied, hCG in the urine binds to the mouse antibodies and starts to travel up the paper into the test region. Antibodies that do not bind to hCG (there are always more antibodies than there is hCG) also move into and through the test region, where they serve as a positive control.[br>[...>[br>At this point (the test has been at work for roughly 3 minutes), an enzyme attached to the first mouse antibody converts a colorless chemical placed in the test window and in the control window to a deep pink color. If the woman has hCG in her urine, the hCG-mouse antibody will be found in two places: the test region and the control region. There will be two color reactions, one in each window. [...> (If a woman was taking fertility drugs, this might give a false positive test, but otherwise, the test is very reliable)."
for Goat , which is he control anti-body in most tests , so to make the tests they use goat and mouse anti-bodies, to react with the chemicals found in urine... if you hand;e goats or mice,(like i do) you may already have a immune response to those anti-bodies and that may also be present in your urine. giving a false negative... it' is similar to immunity to
toxoplasmosis in kitty litter ,if you have already developed an immunity before pregnancy your at a lower risk, BUT you still shouldn't clean the litter box if you can avoid it ..
so final answer , it IS possible for people who handle goats and mice to have a false positive result ...