Acute or chronic inflammation: Mildly elevated serum zinc levels can be seen in various inflammatory conditions, such as infections, autoimmune diseases, or chronic illnesses. This is because zinc is an acute-phase reactant, and its levels can increase in response to inflammation.

Hemolysis: Zinc is released from red blood cells during hemolysis, which can lead to mildly elevated serum zinc levels.
Liver disease: Certain liver conditions, such as cirrhosis or liver cancer, can cause an increase in serum zinc levels due to impaired zinc metabolism.
Renal disease: Kidney damage or disease can lead to impaired zinc excretion, resulting in mildly elevated serum zinc levels.
Tap water contamination: Although less likely, it is possible that contaminated tap water could contribute to mildly elevated serum zinc levels, especially if the water pipes in the patient's house are made of zinc-coated materials or have high levels of zinc leaching into the water.

Hemochromatosis: A genetic disorder characterized by excessive iron absorption, which can also lead to increased zinc absorption and mildly elevated serum zinc levels. Missing this diagnosis could lead to severe iron overload and organ damage.
Wilson's disease: A rare genetic disorder that affects copper metabolism, which can also impact zinc levels. Missing this diagnosis could lead to severe liver and neurological damage.

Zinc toxicity from industrial exposure: Exposure to high levels of zinc in certain industries, such as smelting or welding, can lead to zinc toxicity and mildly elevated serum zinc levels.
Genetic disorders of zinc metabolism: Rare genetic conditions, such as acrodermatitis enteropathica, can affect zinc absorption and metabolism, leading to mildly elevated serum zinc levels.
Certain medications: Some medications, such as those used to treat Wilson's disease or certain antibiotics, can affect zinc levels and lead to mildly elevated serum zinc levels.