Specimen Collection
Preferred specimen:
24h urine collected in a plastic bottle - no acid
Casual and acidified samples acceptable.
Information about contamination of trace element specimens
Reference Intervals
Units:
umol/d
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Reference interval
: < 1.2
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Uncertainty of Measurement: 17%
Turnaround Time: Within 1 week
Performed once a week.
Assay Method
Principle
: Inductively coupled plasma mass spectrometry (ICP-MS)
Instrument
: PlasmaQuant MS Elite
Diagnostic Use and Interpretation
24h urine copper is increased output in Wilson's disease, as well as in chronic active hepatitis, proteinuria, and rheumatoid arthritis. The test is useful only for diagnosing or assessing the treatment of Wilson's disease.
The copper / zinc ratio in a morning spot urine has been reported to be useful as a screening test for Wilson's disease (normal copper / zinc ratio: <0.2)
Penicillamine challenge test
The penicillamine challenge has been standardized in children, where it can be used as an adjunctive test. In children, the test could be helpful in cases where urinary copper excretion is near the upper limit of normal but the suspicion for Wilson disease is high, or conversely, in cases where the urinary copper excretion is mildly elevated but an alternative diagnosis is likely.
The penicillamine challenge is performed by giving a 500 mg dose of penicillamine (regardless of the patient's weight) at the beginning of the 24-hour
urine collection and then again at 12 hours. Urinary copper excretion greater than 25 umol per 24-hours is much more likely in
Wilson disease compared with other types of liver disease.
The penicillamine challenge is unreliable for excluding Wilson disease in asymptomatic siblings, has not been evaluated for differentiating heterozygous carriers from affected homozygotes, and has not been well-standardized in adults.
See also
Copper - liver
Copper - serum
Ceruloplasmin - serum
References
1. Up-to-Date, Sept 2013
Contact Information
Emails to
chemicalpathologist@adhb.govt.nz
will receive priority attention from the on-call chemical pathologist.
If the query concerns a specific patient please include the NHI number in your email.
If email is not a suitable option, please contact the on-call chemical pathologist via
Lablink (Auckland City Hospital ext. 22000 or 09-3078995).
Individual chemical pathologists may be contacted but will not be available at all times.
After-hours
: contact
Lablink (Auckland City Hospital ext. 22000 or 09-3078995) or hospital operator for on duty staff after hours.
Dr Samarina Musaad
(Clinical Lead)
:
SamarinaM@adhb.govt.nz
ext. 22402
Dr Cam Kyle:
CampbellK@adhb.govt.nz
ext 22052
Dr Weldon Chiu:
WeldonC@adhb.govt.nz
ext. 23427
Dr Campbell Heron:
CHeron@adhb.govt.nz
ext. 23427
Dr Sakunthala Jayasinghe:
Sakunthala@adhb.govt.nz
ext. 23427
Specimen Transport Instructions for Referring Laboratories
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Instructions for Referral to Labplus
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Aliquot Instructions
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10 mL urine Fridge 4C minimum aliquot 2 mL urine
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Aliquot Transport to labplus
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4C in leak proof containers
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