Abstract: Objective　To investigate the levels of serum copper biochemical examination [copper ion（Cu²⁺），copper oxidase（SCO）and ceruloplasmin（CP）] in patients with hepato-lenticular degeneration（HLD）and their significance for the diagnosis of HLD.   Methods　By atomic absorption spectrophotometry，hydrochloric acid-p-phenylenediamine colorimetric method and immune turbidimetric method，288 patients with HLD and 90 healthy controls were measured for serum Cu²⁺，SCO and CP levels. The 285 patients with decreasing serum copper biochemical examination levels were classified according to clinical types （42 cases of pseudo-sclerosis type，49 cases of brain-visceral hybrid type，138 cases of liver type and 59 cases of Wilson type） and the age（under 10 years old group，11 to 20 years old group，21 to 30 years old group and ≥31 years old group），and the results of serum copper biochemical examination were compared. Results　In the 288 HLD patients，the results of serum copper biochemical examination of 3 cases were normal，and the abnormality rate was 98.96%. In 285 HLD patients with decreasing levels of serum copper biochemical examination，the serum level of Cu2+ was（2.46±1.73）μmol/L，the serum level of SCO was 0.027 （0.005-0.248）U/L，and the level of CP was （55.07±31.87）mg/L，which were significantly lower than those in controls [(15.09±2.42）μmol/L，0.492（0.269-0.798）U/L and（306.37±46.84)mg/L ]（P＜0.01）. The SCO level in Wilson type group was significantly lower than those in the liver type and pseudo-sclerosis type groups（P＜0.01），and the CP level was significantly lower than those in the liver type and brain-visceral hybrid type groups（P＜0.05，P＜0.01）. The serum Cu2+ level in pseudo-sclerosis type group was higher than those in the other clinical type groups（P＜0.05，P＜0.01）. The serum Cu2+ level was the lowest in under 10 years old group，and the results of serum copper biochemical examination in ≥31 years old group were higher than those in the other age groups. The areas under the receiver operating characteristic（ROC）curve（AUC）were 0.995，0.994 and 0.996，respectively. The optimal cut-off values were 6.34 μmol/L，0.121 U/L and 123.1 mg/L，respectively. The sensitivity，specificity and false identification rate were 95%，100% and 0%. Conclusions　Serum copper biochemical examination is the most convenient screening program for diagnosing HLD. For patients with HLD，the best diagnostic cut-off values are as follows：Cu2+ ≤ 6.34 μmol/L，SCO ≤0.121 U/L and CP ≤123.1 mg/L.

Key words: Copper, Ceruloplasmin, Copper oxidase, Hepato-lenticular degeneration