Indications of Galactose Loading Test
This test has been used to screen for GSD (except in patients presumed to have GSD type I, for whom the test is, in effect, a continuation of the fasting state). It should never be used in patients with galactosuria, since galactose administration is highly toxic in patients with galactosemias.
Procedures of Galactose Loading Test
The preparation is similar to that for the glucose loading test. Galactose (2 g/kg, with a maximum of 50 g) as a 10% solution in water is administered orally over 5-10 min. Blood is sampled twice at zero time and every 30 min until 3-4 h after the completion of galactose ingestion. All blood samples are assayed for glucose and lactate.
Interpretation of Galactose Loading Test
Serum lactate rises above 3.5 mmol/1 and up to 10 mmol/1 in GSD type III, VI and IX.