There can be a lot of variation of clinical signs depending of the severity of the condition, which could depend on how much blood flow is diverted past the liver. Most Maltese will be diagnosed with port-systemic shunts under one year of age, but some several years older have been diagnosed with the condition. The uric acid levels may be elevated in a significant number of those Maltese affected.
Acid levels are extremely important in the diagnostic screening of symptomatic potential shunts.
Fasting and a two hour post meal blood samples are evaluated for bile acid levels. In virtually all porto-systemic shunts there will be a significant rise in the bile acid levels over normal. The use of bile acids in screening clinically normal for liver shunts is not currently being advised due to the variation of normal bile acid levels in Maltese, and other breeds as well. Reports of recent vaccination with modified-live vaccines causing high serum bile acid levels in normal animals have not been confirmed as of this time. Radiography Radiography is one of the most important methods of establishing a diagnosis of porto-systemic shunt, and is currently the only universally accepted method of confirming a shunt, short of major surgery.