From the Guidelines
A slightly low serum copper level with normal urinary copper excretion is likely not indicative of Wilson's disease, and treatment should focus on addressing potential causes of copper deficiency, such as inadequate dietary intake or increased tissue demand. This is based on the findings of a practice guideline on Wilson's disease published in Hepatology in 2003 1. The guideline notes that a low serum copper level can be seen in patients with Wilson's disease, but it is usually accompanied by a decreased ceruloplasmin level and an elevated nonceruloplasmin-bound copper concentration.
Key points to consider in the interpretation of serum copper levels include:
- Serum copper levels can fluctuate, and repeat testing is necessary to confirm consistently low levels
- Normal or elevated serum copper levels in the face of decreased ceruloplasmin levels can indicate an increase in nonceruloplasmin-bound copper
- Nonceruloplasmin-bound copper concentration is a more sensitive indicator of Wilson's disease, but its measurement is dependent on accurate methods for measuring serum copper and ceruloplasmin
- A nonceruloplasmin-bound copper concentration above 25 μg/dL is suggestive of Wilson's disease, but it can also be elevated in other conditions such as acute liver failure, chronic cholestasis, and copper intoxication
In the absence of symptoms or other indications of Wilson's disease, a slightly low serum copper level with normal urinary copper excretion can be managed by:
- Increasing dietary copper intake through foods rich in copper, such as shellfish, nuts, and seeds
- Avoiding medications that can reduce copper absorption, such as zinc supplements and antacids
- Addressing underlying medical conditions that may contribute to copper deficiency, such as malabsorption disorders or severe malnutrition
- Considering supplementation with elemental copper under medical supervision, as excess copper can be harmful 1.
From the Research
Significance of Slightly Low Serum Copper Level with Normal Urinary Copper Excretion
- A slightly low serum copper level with normal urinary copper excretion can be indicative of copper deficiency, which can cause hematological and neurological manifestations 2, 3, 4.
- Copper deficiency can be acquired due to various factors such as gastrointestinal disease or surgery, malabsorption syndromes, and zinc overload, which can impair copper absorption in the upper gastrointestinal tract 2, 4.
- The presence of coexisting neurological or hematological manifestations, such as myeloneuropathy, anemia, and leukopenia, can suggest copper deficiency 2, 3, 4.
- Normal urinary copper excretion can help differentiate copper deficiency from Wilson's disease, which is characterized by low serum copper and high urinary copper levels 2, 4.
- Copper deficiency can also be associated with liver diseases, such as steatohepatitis, iron overload, and malnutrition, and copper supplementation can improve serum copper, ceruloplasmin, and liver function parameters in some cases 5.
- In some cases, a slightly low serum copper level with normal urinary copper excretion can be associated with neurological disorders, such as movement disorders, dysarthria, and spastic gait, although the exact mechanism is not fully understood 6.