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Reducing Substances

Blood Sciences Test


Faecal and urine reducing substances are no longer being offered by the laboratory. This is due to the risk of both false positive and negative results, and lack of published evidence to support using these tests in context of their historical use.

The recommended alternative testing strategies are as follows:

Faecal reducing substances:

historically requested to screen faeces for the presence of lactose to support a diagnosis of lactose intolerance as a cause of osmotic diarrhoea. Trialling a lactose free diet and monitoring symptoms is recommended.

Urine reducing substances:

historically used as a first line screen in infants with prolonged/conjugated jaundice to detect galactosaemia and to diagnose other disorders of carbohydrate metabolism.

Classical Galactosaemia The following alternative tests for galactosaemia are recommended:

  • Galactose uridyl transferase screen in non-transfused patients (sendaway test to Southmead – Lithium heparin whole blood)
  • Random urine galactitol in transfused patients (sendaway test to Southmead) 

Hereditary Fructose Intolerance

Under UK Genetic Testing Network testing criteria, samples for genetic testing of the Aldolase B gene are accepted based on clinical /family history (sendaway to Addenbrookes Hospital, Cambridge).

Please contact the Duty Biochemist Tel: 01392 402935 to discuss the need for any of these tests.

Specimen Labelling Procedure
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