A very useful site that is called Lab Tests Online is a very informative site that gives a wealth of information in regards to learning about lab work, what the tests mean, how they are done etc...
The site also has a very nice section on conditions and diseases. Lupus discussed in the previous post falls into the catagory of a Autoimmune Disorder. There is a very nice discussion here that describes what the immune system is, what autoimmune disorders are and gives a very nice overview of Diabetes, Lupus, Rheumatoid Arthritis, Sjogren's syndrome, and a few other illnessess under this catagorie.
Well worth taking a look at if you are wanting to explore more about these specific illnesses, or just wanting to look up lab work that you have had done and want more information in regards to it. You can find it here:
http://www.labtestsonline.org/understan ... mmune.html
Having a better understanding of the different types of conditions/diseases will help in being able to have more personal control over your own health. Explore these areas and learn what you need to know about yourself and your health issues.