In response to a few questions asked by a LH (an online lupus support group) member.
There are extremely rare manifestations of lupus in which a person's immune system targets the parathyroid. The parathyroid is the place where (unsurprisingly) the parathyroid hormone is produced. This hormone serves to regulate how much calcium is being taken out of or given to the bones. If the parathyroid is targeted then the patient's body may be constantly taking calcium away from the bones. However, there have only been a very few recorded cases of this happening.
A more common reason for high calcium levels in lupus patients is a problem with the kidneys. The kidneys work to regulate fluids and various ions (single atoms that have an electrical charge) in the body. Calcium is one of these ions, so if your calcium levels are high it may mean that the kidney isn't functioning properly and is therefore unable to regulate your calcium levels. A good resource for blood tests commonly run on lupus patients is here.
Increased lymphocyte count while still on methotrexate:
It is totally possible that an increasing lymphocyte count means that the immune system has found a way to get around the methotrexate. But it could also happen for other reasons; if you're fighting a cold or virus your immune system will be producing more lymphocytes (or trying to do so) even before you feel ill. So the best answer I can give is that it could certainly be a sign of your becoming resistant to methotexate, but there are other things that could cause it as well. Obviously your rheumatologist would be the best person to judge whether it's resistance to methotrexate or something else that is causing the increased count.
This is a test to see how much variation there is in the volume of your red blood cells. The actual size of the red blood cells is not what is being described; rather it's a measurement of how different each cell is in comparison with the average of all the cells. I know that is about as clear as mud, so I offer the following analogy:
Let's say that your blood cells are represented by soda bottles. The volume of the cell (soda bottle) is how much that cell (bottle) can hold. If you have ten 2 liter bottles, then you have low variation; each bottle holds about as much as all the other bottles. The same is true if you have ten child-sized cans. However, if you have five 2 liter bottles, three 16 oz individual bottles and two child-sized bottles then your variation is high; the difference between how much each individual bottle can hold is quite large.
This test is performed because the volume of red blood cells can change in different ways for different kinds of anemia. (Which can be caused by low iron, low B12, etc). Different sizes can be associated with different volumes. Wikipedia has a pretty good description of some of the causes here.
As for why your doctor writes it off as a lab error I have absolutely no idea. You'd really have to ask him, as I'm sure there could be different reasons for his decision.
The usual disclaimer applies; I am not a physician, nor do I have any clinical experience whatsoever. I come at it from a research scientist perspective, and no answer I give should be considered a replacement for a doctor's advice. Also, I suffer from serious brain fog, so if I start going on random tangents in the middle of a post, don't be too surprised.