Update

My vet's ears must have been burning because I got a call and a report.

• Blood looks good.  Chemistry, liver, kidneys look good.  
• CBC white blood cells slightly elevated at 1,111
• This can be caused by stress
• Could be allergy
• Or parasites.
• Fecal test last May was negative, so probably not parasites.  Probably stress or allergy.
• Thyroid normal
• Non-sterile urinalysis showed:
• Concentrated sample
• 1+protein
• Protein generally is not desired in urine.
• But it could be caused by the fact that the sample was concentrated.
• Specific gravity was about 10.40, which is near the top (10.50) of the normal range.
• Normally we would look no further but given his lack of energy, he may have a urinary tract infection.  It is possibly an issue.

Next steps: A sterile urinary sample.  This is done by flipping the dog on his back, taking an ultrasound to locate the bladder, and sticking a needle into the bladder to draw a sample.

Vet also said that there is a combo test for tick-borne diseases for $104.40.  This test will provide indications of IGC antibodies activity.  If it is positive, we will start Larsen on doxycycline.  If we start on the regime, we should know after the first few doses whether this is in fact the issue because he will start to recover right away.