BACKGROUND: Adrenomegaly and hypertension are common clinical entities in canine medicine for which testing for pheochromocytoma is recommended. Yet, a validated biochemical test for the diagnosis of pheochromocytoma in dogs does not exist. In human medicine, plasma free metanephrine testing is the diagnostic standard for the biochemical diagnosis of pheochromocytoma. OBJECTIVES: The purpose of this study was to investigate the utility of measurement of plasma free metanephrines in dogs for the diagnosis of pheochromocytoma. METHODS: Plasma free metanephrines were measured in 11 healthy dogs and in 3 dogs confirmed to have a pheochromocytoma. The metanephrine assays were performed at a reference laboratory using high-performance liquid chromatography with electrochemical detection. RESULTS: The plasma free metanephrine and normetanephrine concentrations in 11 healthy dogs were normally distributed and were used to create tentative reference intervals. All 3 dogs with histologically confirmed pheochromocytoma clearly had higher concentrations of plasma free metanephrines. CONCLUSIONS: This pilot study demonstrates the potential utility of plasma free metanephrines levels for the biochemical diagnosis of pheochromocytoma in dogs.
BACKGROUND:Adrenomegaly and hypertension are common clinical entities in canine medicine for which testing for pheochromocytoma is recommended. Yet, a validated biochemical test for the diagnosis of pheochromocytoma in dogs does not exist. In human medicine, plasma free metanephrine testing is the diagnostic standard for the biochemical diagnosis of pheochromocytoma. OBJECTIVES: The purpose of this study was to investigate the utility of measurement of plasma free metanephrines in dogs for the diagnosis of pheochromocytoma. METHODS: Plasma free metanephrines were measured in 11 healthy dogs and in 3 dogs confirmed to have a pheochromocytoma. The metanephrine assays were performed at a reference laboratory using high-performance liquid chromatography with electrochemical detection. RESULTS: The plasma free metanephrine and normetanephrine concentrations in 11 healthy dogs were normally distributed and were used to create tentative reference intervals. All 3 dogs with histologically confirmed pheochromocytoma clearly had higher concentrations of plasma free metanephrines. CONCLUSIONS: This pilot study demonstrates the potential utility of plasma free metanephrines levels for the biochemical diagnosis of pheochromocytoma in dogs.