Laboratory diagnosis of insulinoma in the dog: a retrospective study and a new diagnostic procedure.

Simultaneous insulin and glucose measurements from a single sample are often insufficient for the laboratory diagnosis of insulinoma in the hypoglycaemic dog. Although the simple insulin (microU/litre): glucose (mmol/litre) ratio is best, when the selected threshold is set at 13.5, it is not always efficient to confirm or refute insulinoma. The fasting test consists of collecting four samples on a given day (no accurate time period is set between any two samples) from a fasting dog for simultaneous insulin and glucose measurements to detect at least one abnormal insulinaemia peak.