In order to take this exam you need to be VCP5 certified, beside that there are no training requirements like VCP5.
More information can be found over here;
Well maybe I lived under a rock the last weeks, or VMware have released at least one desktop virtualization certification (VCA-DT), and two other desktop certifications are coming soon: VCP-DT and VCAP-DT.
This is very good news, because before this you only had VCP, VCAP and if you’re very smart even VCDX but they where more or less focused on the vSphere 4 product range, and not on the enterprise desktop products, like for example View.
Here’s a little quote from the VMware certification website about the VMware Certified Associate 4 – Desktop or in short VCA4-DT.
The VMware Certified Associate 4 – Desktop (VCA4-DT) is the first step toward gaining expertise in desktop virtualization and earning the respect and recognition that comes with being VMware Certified. The exam is designed for Desktop System Administrators who seek to demonstrate their ability to manage, monitor and troubleshoot desktop deployments and VMware View components, as well as their knowledge of adjacent, complementary technologies to VMware solutions.
The exam blueprint can be found over here (login required).
The two remaining VMware certifications: VCP-DT and VCAP-DT are not yet released, so no information is available at this moment, once they are released, I will add them to this post as well.