This is never a sign of nothing.

If there are no other symptoms diagnosing what might be wrong can be
very difficult.

Things to consider, cardiomyopathy, almost any kind of GI tumour,
cardiovascular tumours, pancreatic tumours, hepatic tumours etc In the
case of my Sue, who had no other symptoms and appeared to be in the
best of health it was an hepatic hemangiosarcoma. Blood tests did not
point any specific problem and she was only diagnosed during
exploratory surgery. I wish you much better luck than that.

Further tests may or may not give a firm diagnosis but these cases can
be very difficult.
 
Tony (not a vet), Sugar and Suki.
In memory of Sally and Sue.

[Posted in FML 6007]