Wilson's disease laboratory findings
Diagnosis
Wilson's disease may be suspected on the basis of any of the symptoms mentioned above, or when a close relative has been found to have Wilson's. Most patients have slightly abnormal liver function tests such as a raised aspartate transaminase, alanine transaminase and bilirubin level. If the liver damage is significant, albumin may be decreased due to an inability of damaged liver cells to produce this protein; likewise, the prothrombin time (a test of coagulation) may be prolonged as the liver is unable to produce proteins known as clotting factors.[1] Alkaline phosphatase levels are relatively low in patients with Wilson's-related acute liver failure.[2] If there are neurological symptoms, magnetic resonance imaging (MRI) of the brain is usually performed; this shows hyperintensities in the part of the brain called the basal ganglia in the T2 setting.[3]
There is no totally reliable test for Wilson's disease, but levels of ceruloplasmin and copper in the blood, as well of the amount of copper excreted in urine during a 24 hour period, are together used to form an impression of the amount of copper in the body. The gold standard or most ideal test is a liver biopsy.[1]
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Laboratory findings
Ceruloplasmin
Levels of ceruloplasmin are abnormally low (<0.2 gram/liter) in 80-95% of cases.[1]
It can, however, be present at normal levels in people with ongoing inflammation as it is an acute phase protein.
Low ceruloplasmin is also found in Menkes disease and aceruloplasminemia, which are related to, but much rarer than, Wilson's disease.[1][3]
The combination of neurological symptoms, Kayser-Fleisher rings and a low ceruloplasmin level is considered sufficient for the diagnosis of Wilson's disease. In many cases, however, further tests are needed.[3]
Serum and urine copper
Serum copper and more importantly urine copper are elevated in Wilson's disease. Urine is collected for 24 hours in a bottle with a copper-free liner. Levels above 100 μg/24h (1.6 μmol/24h) confirm Wilson's disease, and levels above 40 μg/24h (0.6 μmol/24h) are strongly indicative.[1] High urine copper levels are not unique to Wilson's disease; they are sometimes observed in autoimmune hepatitis and in cholestasis (any disease obstructing the flow of bile from the liver to the small bowel).[3]
In children, the penicillamine test may be used. A 500 mg oral dose of penicillamine is administered, and urine collected for 24 hours. If this contains more than 1600 μg (25 μmol), it is a reliable indicator of Wilson's disease. This test has not been validated in adults.[3]
References
- ↑ 1.0 1.1 1.2 1.3 1.4
- ↑ Shaver WA, Bhatt H, Combes B (1986). "Low serum alkaline phosphatase activity in Wilson's disease". Hepatology. 6 (5): 859–63. doi:10.1002/hep.1840060509. PMID 3758940.
- ↑ 3.0 3.1 3.2 3.3 3.4 Roberts EA, Schilsky ML (2003). "A practice guideline on Wilson disease" (PDF). Hepatology. 37 (6): 1475–92. doi:10.1053/jhep.2003.50252. PMID 12774027.