TESTING FOR NON-GLUCOSE REDUCING SUBSTANCES E.G. GALACTOSE IN URINE IN SUSPECTED GALACTOSEMIA. GLUCOSE AS A REDUCING SUBSTANCE CAN BE EVALUATED BY SPECIFIC URINE TESTING. A NEGATIVE GLUCOSE DIPSTICK RESULT & POSITIVE URINE REDUCING SUBSTANCES RESULT IS CONSISTENT WITH PRESENCE IF NON-GLUCOSE REDUCING SUBSTANCES E.G. GALACTOSE, LACTOSE, FRUCTOSE, MALTOSE ETC.
Test Limitations / Confounders
POOR SPECIFICITY E.G. CAN BE POSITIVE DUE TO SOME DRUGS, ALKAPTONURIA (HOMOGENTISIC ACID). FALSE NEGATIVE RESULTS CAN OCCUR IN GALACTOSEMIA & IF THERE IS A HIGH INDEX OF SUSPICION, SPECIFIC ENZYME & GENETIC TESTING SHOULD BE PERFORMED.