Help?! Invalid test???

Ka
Does anyone know what it means if the line in the 'test' window is already visible before even using the test? I opened the test and the 'test' window already showed a dark negative line. 
It was a generic 'Life Brand' HCG test from Shoppers Drug Mart and the test window should show a plus sign if positive, but when I opened the test it already had one dark line (not a plus) in the test window. Was this an invalid test?? Urgh! I threw away the instructions and can't find anything online. Thanks for your help! 

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