Testing Locations » California » Escondido CA » Quest Diagnostics – Escondido Valley Parkway – Employer Drug Testing Not Offered Quest Diagnostics – Escondido Valley Parkway – Employer Drug Testing Not Offered Quest Diagnostics – Escondido Valley Parkway – Employer Drug Testing Not Offered488 E Valley PkwySuite 314Escondido, CA 92025-3363 United States Located across from old Palomar Hospital at the corner of Pennsylvania and E Valley Parkway.