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Blood test for galactosemia
Last reviewed: 23.04.2024
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The reference values (norm) of the concentration of galactose in the blood of newborns are 0-1.11 mmol / L (0-20 mg%), in older age - below 0.28 mmol / L (5 mg%).
Galactosemia is based on the inadequacy of galactose-1-phosphate uridyltransferase (classical galactosemia ) or, more rarely, galactokinase or galactose-epimerase.
For screening for galactosemia, a method of inhibiting bacterial growth is employed. The study is conducted in newborns, for which blood is taken from the umbilical cord or from the finger to the filter paper. Inhibition of bacterial growth is directly proportional to the concentration of galactose in the blood (normal growth inhibition does not occur).
In quantitative determination, examine serum or urine. In the presence of the disease, the concentration of galactose in the blood can increase to 11.25 mmol / l (300 mg%). Quantification of galactose in the blood is important for assessing the adequacy of diet selection for the patient. With a properly selected diet, the level of galactose in the blood should not exceed 0.15 mmol / l (4 mg%). In healthy newborns, the concentration of galactose in the urine is below 3.33 mmol / day (60 mg / day), later - below 0.08 mmol / day (14 mg / day). In patients with galactosemia, the content of galactose in urine is 18.75-75 mmol / l (500-2000 mg%).
Currently, there are diagnostic kits that allow the quantitative determination of the activity of galactose-1-phosphate uridyltransferase in erythrocytes. This study not only makes it possible to establish the presence of enzyme deficiency, but also to reveal heterozygous carriers of the defective gene.
Galactose is increased in liver diseases, hyperthyroidism, digestive disorders.
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