Tim,
I don't often do penicillamine challenge tests as it is a poorly
tolerated chelating agent, especially in children.
When we do, the protocol is to do 2 baseline measurements of 24h
urinary copper before starting the test, then at 9.00 am on the day of
the test give 500 mg of penicillamine, take blood for copper and
caeruloplasmin, and start a new 24 hour urine copper collection.. A
second dose of 500 mg of penicillamine is given at 9.00 pm at night
and the urine collection for copper terminated at 9.00 am the next
morning. This makes it an in-patient procedure, but if the patient is
going home I would accept the second dose of penicillamine at 6.00 pm.
The interpretation is a that in Wilson's you expect a serum copper of
less than 12 mmol/L with an inappropriately low or undetectable
caeruloplasmin and an incremental excretion of urine copper of greater
than 20 mmol/L.
Reference: da Costa DM, Baldwin D, Portmann B, Lolin Y, Mowat A,
Mieli-Vergani G. Value of urinary copper excretion after penicillamine
challenge in the diagnosis of Wilson's disease. Hepatology
1992;15:609-615
Glad to see you are using dynamic testing to make your diagnoses of
metal toxicity!
Nick Miller
London
On 18/10/2007, Reynolds Tim <[log in to unmask]> wrote:
> I need to organise a penicillamine challenge test for a patient with
> probable Wilson's disease there are lots of references to this test on
> the net but they all give instructions like this:
>
> Following penicillamine 0.5 g 12 hourly x 2, urine copper exceeds 25
> micromol/24 hour in 88% patients with WD and 2% with other liver
> disorders.
>
> Does anyone know the precise time schedule relating the penicillamine
> should be taken and the time the urine collection starts?
>
> i.e. is it start both penicillamine and collection at the same time, or
> is there a lag between taking the drug and starting th eurine
> collection?
>
> TIM
>
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