Could be many things. It's hard to answer without knowing more details. What's the device? Is it an IC? Discrete? CMOS? Bipolar? How big is the leakage current?
Again, you need to provide mode details. It's free to write, don't skimp on details. If you want others to help you, then you need to help them first. Describe what you know in as much details as possible.
What's the device? Part number? uA range can be from 1 to 999uA. There are many CMOS ICs out there with input leakage specifications of 10uA. Failing how? What's it in use for? Circuit?