Hello there nana684 I to have Oligoclonal Banding in my spinal fluid and to answer your question Is it always MS? No. Other diseases can cause this such as Lyme disease, certain STD's and various other conditions that involve the blood brain barrier. If I'm not mistaken Oligolonal banding is a marker for inflammation in the nervous system or when a pathogen has crossed the blood brain barrier.
I've been monitored every 4 months via MRI to keep track of the lesions on my brain and spine and when both the banding and lesions were put together thats when my doctors decided to confirm and treat for MS.
A lot of people get confused regarding the banding because on most lab reports from a lumbar puncture they run an MS panel which lists Oligoclonal banding positive or negative as a preliminary test to find more evidence.
Hope this helps
Mike