Metabolic

The metabolic section includes high performance liquid chromatography (HPLC) assays to assess biogenic amine production. Sympathoadrenal catecholamine production is assessed using urine catecholamines/metanephrines, enterochromaffin serotonin using urine 5HIAA. HPLC is considered the reference method and permits separation from interfering substances; this means that we do not need to ask the patient to observe dietary or pharmacological limitations in the first instance. We also offer Vitamin A and Vitamin E analysis by HPLC. These services are supported by Dr Emma Walker.

A close association between the laboratory and Imperial College Healthcare NHS Trust clinicians has permitted us to fine-tune our quoted reference intervals for biogenic amines to give 95% specificity, thereby minimising false positives without any significant impact on diagnostic sensitivity.

Whilst our current practice is to ask for an acidified 24 hour urine collection in all patients except those under 10 years of age, we are currently assessing whether we can derive equally valuable information using a random urine sample. We’re also reassessing the stability of the biogenic amines – our hope is that patients are spared the complications of urine collection and acidification. Simple sample collection, high quality measurement and pertinent interpretation are our goals.

This laboratory also performs initial investigations for porphyria (urine porphyrins and PBG screens; any positive results will be sent for further analysis at a specialist porphyria centre) and sugar metabolism. Urine and faecal samples are screened for reducing substances and the sugars in positive samples are then identified. This service is supported by Sophie Barnes.

The section is active in service development and we are currently validating a renal stone service which will be offered from later this year.

We offer whole gene sequencing for the genetic diagnosis of Primary Hyperoxaluria types 1, 2 and 3 and for a number of steroidogenic defects. To enquire about this service please contact Dr Emma Walker on [email protected].

Click here to download the molecular test request form