Allopurinol load test for OTC

After an allopurinol load, levels of orotic acid and orotidine are increased in timed urine samples of patients heterozygous for a defect in the urea cycle enzyme ornithine transcarbamylase. Orotic acid and orotidine are measured by an HPLC method.
Clinical details: 
The allopurinol load test is used to detect female carriers of the X-linked urea cycle disorder ornithine transcarbamylase deficiency (OTC). When OTC carrier females are loaded with allopurinol, orotic acid and orotidine accumulate to abnormal levels in timed urine samples.
Reference range: 

Please contact the laboratory to discuss

Sample type and Volume required: 
3 x 8h urine collection + baseline urine
Turnaround time: 
2 weeks
Storage and transport: 
Contact laboratory for protocol
Purine Research Laboratory at St Thomas'
020 7188 1266
St Thomas’ Hospital
North Wing - 4th Floor
Westminster Bridge Road
London SE1 7EH
For clinical advice or interpretation of results, please contact the laboratory in the first instance.

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Last updated: 15/12/2015