Was this your GP or a rheumatologist?
Most auto-immune diseases, including the ones you've mentioned, are diagnosed not just on blood tests but on a complete evaluation of symptoms. Drs who exclude these illnesses based strictly on blood results are not following the newest diagnostic protocols. (And are often GP's, you really need to see a rheumatologist.)
Lynnwood, Lupus & Sjogren's Moderator, Dx: 2002DIAGNOSING LUPUS & HW's LUPUS 101
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