AFE4900: How to tell if sensor is in contact with human body

Part Number:AFE4900

Hi team,

I have a customer who uses the AFE4900 in a shipping product and they are trying to add firmware updates. They asked me how they might be able to tell if the sensor is or isn't in contact with a human body. I cannot see the datasheet so I can't see the register map. They are asking for any example code we might have written that we could pass along to give them the jist of how to do it. If that isn't available, an explanation of how they might pull that off using existing status registers would be appreciated. 

Feel free to take this offline with me if info is sensitive.

Thanks,

Brian