At www.virustotal.com you can analyze a file to determine if it presents a threat. Virus Total was begun by a Spanish company, but is currently operated by Google, which presumably is a basis for regarding it s a service with a great deal of integrity. Virus Total collects information from multiple antivirus engines and website scanners, including AVG, BitDefender, Kaspersky, McAfee, Symantec, and more than 50 other antivirus products. It also uses different tools to determine the format of tiles.
When you upload a file to the site, Virus Total generates a list indicating which of the antivirus productions have listed the file as a threat.
It also provides a more detailed report which among other information, shows if the signature of the file has been verified.