Direct measurement of serum non-caeruloplasmin copper in liver disease

The serum non-caeruloplasmin copper concentrations were measured in normal subjects and patients with various types of liver disease by a sensitive direct method involving complexing the copper and measurement by atomic absorption spectrophotometry. In normal subjects the mean concentration (+/- S.D.) was 10.1 +/- 1.6 mug/100 ml, males having a slightly higher value (10.7 +/- 1.3 mug/100 ml) than females (9.2 +/- 1.8 mug/100 ml). In patients with various non-hepatic diseases concentrations were raised (15.8 +/- 8.9 mug/100 ml), as also in hepatitis (14.7 +/- 4.3 mug/100 ml), cholestasis (16.1 +/- 6.4 mug/100 ml) and cirrhosis (16.3 +/- 8.7 mug/100 ml). Heterozygotes for Wilson's disease and patients treated for Wilson's disease had concentrations (12.9 +/- 5.9 and 9.8 +/- 3.7 mug/100 ml, respectively) which did not differ significantly from normal whereas untreated patients had very significantly raised concentrations (22.9 +/- 4.5 mug/100 ml). Direct measurement of serum non-caeruloplasmin copper is more accurate than indirect measurement and may help in assessing the effect of treatment but it is concluded that measurement of this fraction of serum copper will not enable Wilson's disease to be differentiated from other forms of liver disease.